build: Add some required modules for node

9 files changed, 2253 insertions, 0 deletions

diff --git a/node_modules/readable-stream/lib/_stream_duplex.js b/node_modules/readable-stream/lib/_stream_duplex.js
new file mode 100644
index 0000000..a1ca813
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_duplex.js
@@ -0,0 +1,131 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+/*<replacement>*/
+var objectKeys = Object.keys || function (obj) {
+  var keys = [];
+  for (var key in obj) {
+    keys.push(key);
+  }return keys;
+};
+/*</replacement>*/
+
+module.exports = Duplex;
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+var Readable = require('./_stream_readable');
+var Writable = require('./_stream_writable');
+
+util.inherits(Duplex, Readable);
+
+{
+  // avoid scope creep, the keys array can then be collected
+  var keys = objectKeys(Writable.prototype);
+  for (var v = 0; v < keys.length; v++) {
+    var method = keys[v];
+    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
+  }
+}
+
+function Duplex(options) {
+  if (!(this instanceof Duplex)) return new Duplex(options);
+
+  Readable.call(this, options);
+  Writable.call(this, options);
+
+  if (options && options.readable === false) this.readable = false;
+
+  if (options && options.writable === false) this.writable = false;
+
+  this.allowHalfOpen = true;
+  if (options && options.allowHalfOpen === false) this.allowHalfOpen = false;
+
+  this.once('end', onend);
+}
+
+Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function () {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// the no-half-open enforcer
+function onend() {
+  // if we allow half-open state, or if the writable side ended,
+  // then we're ok.
+  if (this.allowHalfOpen || this._writableState.ended) return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  pna.nextTick(onEndNT, this);
+}
+
+function onEndNT(self) {
+  self.end();
+}
+
+Object.defineProperty(Duplex.prototype, 'destroyed', {
+  get: function () {
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed && this._writableState.destroyed;
+  },
+  set: function (value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+    this._writableState.destroyed = value;
+  }
+});
+
+Duplex.prototype._destroy = function (err, cb) {
+  this.push(null);
+  this.end();
+
+  pna.nextTick(cb, err);
+};
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/_stream_passthrough.js b/node_modules/readable-stream/lib/_stream_passthrough.js
new file mode 100644
index 0000000..a9c8358
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,47 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+'use strict';
+
+module.exports = PassThrough;
+
+var Transform = require('./_stream_transform');
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+util.inherits(PassThrough, Transform);
+
+function PassThrough(options) {
+  if (!(this instanceof PassThrough)) return new PassThrough(options);
+
+  Transform.call(this, options);
+}
+
+PassThrough.prototype._transform = function (chunk, encoding, cb) {
+  cb(null, chunk);
+};
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/_stream_readable.js b/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 0000000..bf34ac6
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,1019 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+module.exports = Readable;
+
+/*<replacement>*/
+var isArray = require('isarray');
+/*</replacement>*/
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+
+/*<replacement>*/
+var EE = require('events').EventEmitter;
+
+var EElistenerCount = function (emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+/*<replacement>*/
+
+var Buffer = require('safe-buffer').Buffer;
+var OurUint8Array = global.Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*</replacement>*/
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+/*<replacement>*/
+var debugUtil = require('util');
+var debug = void 0;
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
+} else {
+  debug = function () {};
+}
+/*</replacement>*/
+
+var BufferList = require('./internal/streams/BufferList');
+var destroyImpl = require('./internal/streams/destroy');
+var StringDecoder;
+
+util.inherits(Readable, Stream);
+
+var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn);
+
+  // This is a hack to make sure that our error handler is attached before any
+  // userland ones.  NEVER DO THIS. This is here only because this code needs
+  // to continue to work with older versions of Node.js that do not include
+  // the prependListener() method. The goal is to eventually remove this hack.
+  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+}
+
+function ReadableState(options, stream) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  var isDuplex = stream instanceof Duplex;
+
+  // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+  this.objectMode = !!options.objectMode;
+
+  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode;
+
+  // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+  var hwm = options.highWaterMark;
+  var readableHwm = options.readableHighWaterMark;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+
+  if (hwm || hwm === 0) this.highWaterMark = hwm;else if (isDuplex && (readableHwm || readableHwm === 0)) this.highWaterMark = readableHwm;else this.highWaterMark = defaultHwm;
+
+  // cast to ints.
+  this.highWaterMark = Math.floor(this.highWaterMark);
+
+  // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false;
+
+  // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+  this.sync = true;
+
+  // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // the number of writers that are awaiting a drain event in .pipe()s
+  this.awaitDrain = 0;
+
+  // if true, a maybeReadMore has been scheduled
+  this.readingMore = false;
+
+  this.decoder = null;
+  this.encoding = null;
+  if (options.encoding) {
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+
+function Readable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  if (!(this instanceof Readable)) return new Readable(options);
+
+  this._readableState = new ReadableState(options, this);
+
+  // legacy
+  this.readable = true;
+
+  if (options) {
+    if (typeof options.read === 'function') this._read = options.read;
+
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+  }
+
+  Stream.call(this);
+}
+
+Object.defineProperty(Readable.prototype, 'destroyed', {
+  get: function () {
+    if (this._readableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed;
+  },
+  set: function (value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._readableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+  }
+});
+
+Readable.prototype.destroy = destroyImpl.destroy;
+Readable.prototype._undestroy = destroyImpl.undestroy;
+Readable.prototype._destroy = function (err, cb) {
+  this.push(null);
+  cb(err);
+};
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function (chunk, encoding) {
+  var state = this._readableState;
+  var skipChunkCheck;
+
+  if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      encoding = encoding || state.defaultEncoding;
+      if (encoding !== state.encoding) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = '';
+      }
+      skipChunkCheck = true;
+    }
+  } else {
+    skipChunkCheck = true;
+  }
+
+  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function (chunk) {
+  return readableAddChunk(this, chunk, null, true, false);
+};
+
+function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
+  var state = stream._readableState;
+  if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else {
+    var er;
+    if (!skipChunkCheck) er = chunkInvalid(state, chunk);
+    if (er) {
+      stream.emit('error', er);
+    } else if (state.objectMode || chunk && chunk.length > 0) {
+      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+        chunk = _uint8ArrayToBuffer(chunk);
+      }
+
+      if (addToFront) {
+        if (state.endEmitted) stream.emit('error', new Error('stream.unshift() after end event'));else addChunk(stream, state, chunk, true);
+      } else if (state.ended) {
+        stream.emit('error', new Error('stream.push() after EOF'));
+      } else {
+        state.reading = false;
+        if (state.decoder && !encoding) {
+          chunk = state.decoder.write(chunk);
+          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
+        } else {
+          addChunk(stream, state, chunk, false);
+        }
+      }
+    } else if (!addToFront) {
+      state.reading = false;
+    }
+  }
+
+  return needMoreData(state);
+}
+
+function addChunk(stream, state, chunk, addToFront) {
+  if (state.flowing && state.length === 0 && !state.sync) {
+    stream.emit('data', chunk);
+    stream.read(0);
+  } else {
+    // update the buffer info.
+    state.length += state.objectMode ? 1 : chunk.length;
+    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
+
+    if (state.needReadable) emitReadable(stream);
+  }
+  maybeReadMore(stream, state);
+}
+
+function chunkInvalid(state, chunk) {
+  var er;
+  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  return er;
+}
+
+// if it's past the high water mark, we can push in some more.
+// Also, if we have no data yet, we can stand some
+// more bytes.  This is to work around cases where hwm=0,
+// such as the repl.  Also, if the push() triggered a
+// readable event, and the user called read(largeNumber) such that
+// needReadable was set, then we ought to push more, so that another
+// 'readable' event will be triggered.
+function needMoreData(state) {
+  return !state.ended && (state.needReadable || state.length < state.highWaterMark || state.length === 0);
+}
+
+Readable.prototype.isPaused = function () {
+  return this._readableState.flowing === false;
+};
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function (enc) {
+  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+  this._readableState.decoder = new StringDecoder(enc);
+  this._readableState.encoding = enc;
+  return this;
+};
+
+// Don't raise the hwm > 8MB
+var MAX_HWM = 0x800000;
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function howMuchToRead(n, state) {
+  if (n <= 0 || state.length === 0 && state.ended) return 0;
+  if (state.objectMode) return 1;
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
+  }
+  // If we're asking for more than the current hwm, then raise the hwm.
+  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length) return n;
+  // Don't have enough
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+  return state.length;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function (n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+
+  if (n !== 0) state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 && state.needReadable && (state.length >= state.highWaterMark || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
+    return null;
+  }
+
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0) endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true;
+    // if the length is currently zero, then we *need* a readable event.
+    if (state.length === 0) state.needReadable = true;
+    // call internal read method
+    this._read(state.highWaterMark);
+    state.sync = false;
+    // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+    if (!state.reading) n = howMuchToRead(nOrig, state);
+  }
+
+  var ret;
+  if (n > 0) ret = fromList(n, state);else ret = null;
+
+  if (ret === null) {
+    state.needReadable = true;
+    n = 0;
+  } else {
+    state.length -= n;
+  }
+
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended) state.needReadable = true;
+
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
+
+  if (ret !== null) this.emit('data', ret);
+
+  return ret;
+};
+
+function onEofChunk(stream, state) {
+  if (state.ended) return;
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+
+  // emit 'readable' now to make sure it gets picked up.
+  emitReadable(stream);
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    if (state.sync) pna.nextTick(emitReadable_, stream);else emitReadable_(stream);
+  }
+}
+
+function emitReadable_(stream) {
+  debug('emit readable');
+  stream.emit('readable');
+  flow(stream);
+}
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    pna.nextTick(maybeReadMore_, stream, state);
+  }
+}
+
+function maybeReadMore_(stream, state) {
+  var len = state.length;
+  while (!state.reading && !state.flowing && !state.ended && state.length < state.highWaterMark) {
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length)
+      // didn't get any data, stop spinning.
+      break;else len = state.length;
+  }
+  state.readingMore = false;
+}
+
+// abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+Readable.prototype._read = function (n) {
+  this.emit('error', new Error('_read() is not implemented'));
+};
+
+Readable.prototype.pipe = function (dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
+
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted) pna.nextTick(endFn);else src.once('end', endFn);
+
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable, unpipeInfo) {
+    debug('onunpipe');
+    if (readable === src) {
+      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
+        unpipeInfo.hasUnpiped = true;
+        cleanup();
+      }
+    }
+  }
+
+  function onend() {
+    debug('onend');
+    dest.end();
+  }
+
+  // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+
+  var cleanedUp = false;
+  function cleanup() {
+    debug('cleanup');
+    // cleanup event handlers once the pipe is broken
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+
+    cleanedUp = true;
+
+    // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
+  }
+
+  // If the user pushes more data while we're writing to dest then we'll end up
+  // in ondata again. However, we only want to increase awaitDrain once because
+  // dest will only emit one 'drain' event for the multiple writes.
+  // => Introduce a guard on increasing awaitDrain.
+  var increasedAwaitDrain = false;
+  src.on('data', ondata);
+  function ondata(chunk) {
+    debug('ondata');
+    increasedAwaitDrain = false;
+    var ret = dest.write(chunk);
+    if (false === ret && !increasedAwaitDrain) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
+        debug('false write response, pause', src._readableState.awaitDrain);
+        src._readableState.awaitDrain++;
+        increasedAwaitDrain = true;
+      }
+      src.pause();
+    }
+  }
+
+  // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EElistenerCount(dest, 'error') === 0) dest.emit('error', er);
+  }
+
+  // Make sure our error handler is attached before userland ones.
+  prependListener(dest, 'error', onerror);
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+
+  return dest;
+};
+
+function pipeOnDrain(src) {
+  return function () {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain) state.awaitDrain--;
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+
+Readable.prototype.unpipe = function (dest) {
+  var state = this._readableState;
+  var unpipeInfo = { hasUnpiped: false };
+
+  // if we're not piping anywhere, then do nothing.
+  if (state.pipesCount === 0) return this;
+
+  // just one destination.  most common case.
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes) return this;
+
+    if (!dest) dest = state.pipes;
+
+    // got a match.
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest) dest.emit('unpipe', this, unpipeInfo);
+    return this;
+  }
+
+  // slow case. multiple pipe destinations.
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+
+    for (var i = 0; i < len; i++) {
+      dests[i].emit('unpipe', this, unpipeInfo);
+    }return this;
+  }
+
+  // try to find the right one.
+  var index = indexOf(state.pipes, dest);
+  if (index === -1) return this;
+
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
+
+  dest.emit('unpipe', this, unpipeInfo);
+
+  return this;
+};
+
+// set up data events if they are asked for
+// Ensure readable listeners eventually get something
+Readable.prototype.on = function (ev, fn) {
+  var res = Stream.prototype.on.call(this, ev, fn);
+
+  if (ev === 'data') {
+    // Start flowing on next tick if stream isn't explicitly paused
+    if (this._readableState.flowing !== false) this.resume();
+  } else if (ev === 'readable') {
+    var state = this._readableState;
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.emittedReadable = false;
+      if (!state.reading) {
+        pna.nextTick(nReadingNextTick, this);
+      } else if (state.length) {
+        emitReadable(this);
+      }
+    }
+  }
+
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+}
+
+// pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+Readable.prototype.resume = function () {
+  var state = this._readableState;
+  if (!state.flowing) {
+    debug('resume');
+    state.flowing = true;
+    resume(this, state);
+  }
+  return this;
+};
+
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    pna.nextTick(resume_, stream, state);
+  }
+}
+
+function resume_(stream, state) {
+  if (!state.reading) {
+    debug('resume read 0');
+    stream.read(0);
+  }
+
+  state.resumeScheduled = false;
+  state.awaitDrain = 0;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading) stream.read(0);
+}
+
+Readable.prototype.pause = function () {
+  debug('call pause flowing=%j', this._readableState.flowing);
+  if (false !== this._readableState.flowing) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+  return this;
+};
+
+function flow(stream) {
+  var state = stream._readableState;
+  debug('flow', state.flowing);
+  while (state.flowing && stream.read() !== null) {}
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function (stream) {
+  var _this = this;
+
+  var state = this._readableState;
+  var paused = false;
+
+  stream.on('end', function () {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length) _this.push(chunk);
+    }
+
+    _this.push(null);
+  });
+
+  stream.on('data', function (chunk) {
+    debug('wrapped data');
+    if (state.decoder) chunk = state.decoder.write(chunk);
+
+    // don't skip over falsy values in objectMode
+    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
+
+    var ret = _this.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function (method) {
+        return function () {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  }
+
+  // proxy certain important events.
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
+  }
+
+  // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+  this._read = function (n) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+
+  return this;
+};
+
+Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function () {
+    return this._readableState.highWaterMark;
+  }
+});
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0) return null;
+
+  var ret;
+  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.head.data;else ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = fromListPartial(n, state.buffer, state.decoder);
+  }
+
+  return ret;
+}
+
+// Extracts only enough buffered data to satisfy the amount requested.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromListPartial(n, list, hasStrings) {
+  var ret;
+  if (n < list.head.data.length) {
+    // slice is the same for buffers and strings
+    ret = list.head.data.slice(0, n);
+    list.head.data = list.head.data.slice(n);
+  } else if (n === list.head.data.length) {
+    // first chunk is a perfect match
+    ret = list.shift();
+  } else {
+    // result spans more than one buffer
+    ret = hasStrings ? copyFromBufferString(n, list) : copyFromBuffer(n, list);
+  }
+  return ret;
+}
+
+// Copies a specified amount of characters from the list of buffered data
+// chunks.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function copyFromBufferString(n, list) {
+  var p = list.head;
+  var c = 1;
+  var ret = p.data;
+  n -= ret.length;
+  while (p = p.next) {
+    var str = p.data;
+    var nb = n > str.length ? str.length : n;
+    if (nb === str.length) ret += str;else ret += str.slice(0, n);
+    n -= nb;
+    if (n === 0) {
+      if (nb === str.length) {
+        ++c;
+        if (p.next) list.head = p.next;else list.head = list.tail = null;
+      } else {
+        list.head = p;
+        p.data = str.slice(nb);
+      }
+      break;
+    }
+    ++c;
+  }
+  list.length -= c;
+  return ret;
+}
+
+// Copies a specified amount of bytes from the list of buffered data chunks.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function copyFromBuffer(n, list) {
+  var ret = Buffer.allocUnsafe(n);
+  var p = list.head;
+  var c = 1;
+  p.data.copy(ret);
+  n -= p.data.length;
+  while (p = p.next) {
+    var buf = p.data;
+    var nb = n > buf.length ? buf.length : n;
+    buf.copy(ret, ret.length - n, 0, nb);
+    n -= nb;
+    if (n === 0) {
+      if (nb === buf.length) {
+        ++c;
+        if (p.next) list.head = p.next;else list.head = list.tail = null;
+      } else {
+        list.head = p;
+        p.data = buf.slice(nb);
+      }
+      break;
+    }
+    ++c;
+  }
+  list.length -= c;
+  return ret;
+}
+
+function endReadable(stream) {
+  var state = stream._readableState;
+
+  // If we get here before consuming all the bytes, then that is a
+  // bug in node.  Should never happen.
+  if (state.length > 0) throw new Error('"endReadable()" called on non-empty stream');
+
+  if (!state.endEmitted) {
+    state.ended = true;
+    pna.nextTick(endReadableNT, state, stream);
+  }
+}
+
+function endReadableNT(state, stream) {
+  // Check that we didn't get one last unshift.
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+  }
+}
+
+function indexOf(xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+  return -1;
+}
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/_stream_transform.js b/node_modules/readable-stream/lib/_stream_transform.js
new file mode 100644
index 0000000..5d1f8b8
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_transform.js
@@ -0,0 +1,214 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+'use strict';
+
+module.exports = Transform;
+
+var Duplex = require('./_stream_duplex');
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+util.inherits(Transform, Duplex);
+
+function afterTransform(er, data) {
+  var ts = this._transformState;
+  ts.transforming = false;
+
+  var cb = ts.writecb;
+
+  if (!cb) {
+    return this.emit('error', new Error('write callback called multiple times'));
+  }
+
+  ts.writechunk = null;
+  ts.writecb = null;
+
+  if (data != null) // single equals check for both `null` and `undefined`
+    this.push(data);
+
+  cb(er);
+
+  var rs = this._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    this._read(rs.highWaterMark);
+  }
+}
+
+function Transform(options) {
+  if (!(this instanceof Transform)) return new Transform(options);
+
+  Duplex.call(this, options);
+
+  this._transformState = {
+    afterTransform: afterTransform.bind(this),
+    needTransform: false,
+    transforming: false,
+    writecb: null,
+    writechunk: null,
+    writeencoding: null
+  };
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+
+  if (options) {
+    if (typeof options.transform === 'function') this._transform = options.transform;
+
+    if (typeof options.flush === 'function') this._flush = options.flush;
+  }
+
+  // When the writable side finishes, then flush out anything remaining.
+  this.on('prefinish', prefinish);
+}
+
+function prefinish() {
+  var _this = this;
+
+  if (typeof this._flush === 'function') {
+    this._flush(function (er, data) {
+      done(_this, er, data);
+    });
+  } else {
+    done(this, null, null);
+  }
+}
+
+Transform.prototype.push = function (chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function (chunk, encoding, cb) {
+  throw new Error('_transform() is not implemented');
+};
+
+Transform.prototype._write = function (chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function (n) {
+  var ts = this._transformState;
+
+  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+
+Transform.prototype._destroy = function (err, cb) {
+  var _this2 = this;
+
+  Duplex.prototype._destroy.call(this, err, function (err2) {
+    cb(err2);
+    _this2.emit('close');
+  });
+};
+
+function done(stream, er, data) {
+  if (er) return stream.emit('error', er);
+
+  if (data != null) // single equals check for both `null` and `undefined`
+    stream.push(data);
+
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  if (stream._writableState.length) throw new Error('Calling transform done when ws.length != 0');
+
+  if (stream._transformState.transforming) throw new Error('Calling transform done when still transforming');
+
+  return stream.push(null);
+}
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/_stream_writable.js b/node_modules/readable-stream/lib/_stream_writable.js
new file mode 100644
index 0000000..b3f4e85
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_writable.js
@@ -0,0 +1,687 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+module.exports = Writable;
+
+/* <replacement> */
+function WriteReq(chunk, encoding, cb) {
+  this.chunk = chunk;
+  this.encoding = encoding;
+  this.callback = cb;
+  this.next = null;
+}
+
+// It seems a linked list but it is not
+// there will be only 2 of these for each stream
+function CorkedRequest(state) {
+  var _this = this;
+
+  this.next = null;
+  this.entry = null;
+  this.finish = function () {
+    onCorkedFinish(_this, state);
+  };
+}
+/* </replacement> */
+
+/*<replacement>*/
+var asyncWrite = !process.browser && ['v0.10', 'v0.9.'].indexOf(process.version.slice(0, 5)) > -1 ? setImmediate : pna.nextTick;
+/*</replacement>*/
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+/*<replacement>*/
+var internalUtil = {
+  deprecate: require('util-deprecate')
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+/*<replacement>*/
+
+var Buffer = require('safe-buffer').Buffer;
+var OurUint8Array = global.Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*</replacement>*/
+
+var destroyImpl = require('./internal/streams/destroy');
+
+util.inherits(Writable, Stream);
+
+function nop() {}
+
+function WritableState(options, stream) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  var isDuplex = stream instanceof Duplex;
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+
+  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  var hwm = options.highWaterMark;
+  var writableHwm = options.writableHighWaterMark;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+
+  if (hwm || hwm === 0) this.highWaterMark = hwm;else if (isDuplex && (writableHwm || writableHwm === 0)) this.highWaterMark = writableHwm;else this.highWaterMark = defaultHwm;
+
+  // cast to ints.
+  this.highWaterMark = Math.floor(this.highWaterMark);
+
+  // if _final has been called
+  this.finalCalled = false;
+
+  // drain event flag.
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called immediately,
+  // or on a later tick.  We set this to true at first, because any
+  // actions that shouldn't happen until "later" should generally also
+  // not happen before the first write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = function (er) {
+    onwrite(stream, er);
+  };
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+
+  this.bufferedRequest = null;
+  this.lastBufferedRequest = null;
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+
+  // count buffered requests
+  this.bufferedRequestCount = 0;
+
+  // allocate the first CorkedRequest, there is always
+  // one allocated and free to use, and we maintain at most two
+  this.corkedRequestsFree = new CorkedRequest(this);
+}
+
+WritableState.prototype.getBuffer = function getBuffer() {
+  var current = this.bufferedRequest;
+  var out = [];
+  while (current) {
+    out.push(current);
+    current = current.next;
+  }
+  return out;
+};
+
+(function () {
+  try {
+    Object.defineProperty(WritableState.prototype, 'buffer', {
+      get: internalUtil.deprecate(function () {
+        return this.getBuffer();
+      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
+    });
+  } catch (_) {}
+})();
+
+// Test _writableState for inheritance to account for Duplex streams,
+// whose prototype chain only points to Readable.
+var realHasInstance;
+if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
+  realHasInstance = Function.prototype[Symbol.hasInstance];
+  Object.defineProperty(Writable, Symbol.hasInstance, {
+    value: function (object) {
+      if (realHasInstance.call(this, object)) return true;
+      if (this !== Writable) return false;
+
+      return object && object._writableState instanceof WritableState;
+    }
+  });
+} else {
+  realHasInstance = function (object) {
+    return object instanceof this;
+  };
+}
+
+function Writable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  // Writable ctor is applied to Duplexes, too.
+  // `realHasInstance` is necessary because using plain `instanceof`
+  // would return false, as no `_writableState` property is attached.
+
+  // Trying to use the custom `instanceof` for Writable here will also break the
+  // Node.js LazyTransform implementation, which has a non-trivial getter for
+  // `_writableState` that would lead to infinite recursion.
+  if (!realHasInstance.call(Writable, this) && !(this instanceof Duplex)) {
+    return new Writable(options);
+  }
+
+  this._writableState = new WritableState(options, this);
+
+  // legacy.
+  this.writable = true;
+
+  if (options) {
+    if (typeof options.write === 'function') this._write = options.write;
+
+    if (typeof options.writev === 'function') this._writev = options.writev;
+
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+
+    if (typeof options.final === 'function') this._final = options.final;
+  }
+
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function () {
+  this.emit('error', new Error('Cannot pipe, not readable'));
+};
+
+function writeAfterEnd(stream, cb) {
+  var er = new Error('write after end');
+  // TODO: defer error events consistently everywhere, not just the cb
+  stream.emit('error', er);
+  pna.nextTick(cb, er);
+}
+
+// Checks that a user-supplied chunk is valid, especially for the particular
+// mode the stream is in. Currently this means that `null` is never accepted
+// and undefined/non-string values are only allowed in object mode.
+function validChunk(stream, state, chunk, cb) {
+  var valid = true;
+  var er = false;
+
+  if (chunk === null) {
+    er = new TypeError('May not write null values to stream');
+  } else if (typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  if (er) {
+    stream.emit('error', er);
+    pna.nextTick(cb, er);
+    valid = false;
+  }
+  return valid;
+}
+
+Writable.prototype.write = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+  var isBuf = !state.objectMode && _isUint8Array(chunk);
+
+  if (isBuf && !Buffer.isBuffer(chunk)) {
+    chunk = _uint8ArrayToBuffer(chunk);
+  }
+
+  if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
+
+  if (typeof cb !== 'function') cb = nop;
+
+  if (state.ended) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
+  }
+
+  return ret;
+};
+
+Writable.prototype.cork = function () {
+  var state = this._writableState;
+
+  state.corked++;
+};
+
+Writable.prototype.uncork = function () {
+  var state = this._writableState;
+
+  if (state.corked) {
+    state.corked--;
+
+    if (!state.writing && !state.corked && !state.finished && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
+  }
+};
+
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+  // node::ParseEncoding() requires lower case.
+  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
+  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new TypeError('Unknown encoding: ' + encoding);
+  this._writableState.defaultEncoding = encoding;
+  return this;
+};
+
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
+    chunk = Buffer.from(chunk, encoding);
+  }
+  return chunk;
+}
+
+Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function () {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
+  if (!isBuf) {
+    var newChunk = decodeChunk(state, chunk, encoding);
+    if (chunk !== newChunk) {
+      isBuf = true;
+      encoding = 'buffer';
+      chunk = newChunk;
+    }
+  }
+  var len = state.objectMode ? 1 : chunk.length;
+
+  state.length += len;
+
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret) state.needDrain = true;
+
+  if (state.writing || state.corked) {
+    var last = state.lastBufferedRequest;
+    state.lastBufferedRequest = {
+      chunk: chunk,
+      encoding: encoding,
+      isBuf: isBuf,
+      callback: cb,
+      next: null
+    };
+    if (last) {
+      last.next = state.lastBufferedRequest;
+    } else {
+      state.bufferedRequest = state.lastBufferedRequest;
+    }
+    state.bufferedRequestCount += 1;
+  } else {
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+  }
+
+  return ret;
+}
+
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+
+function onwriteError(stream, state, sync, er, cb) {
+  --state.pendingcb;
+
+  if (sync) {
+    // defer the callback if we are being called synchronously
+    // to avoid piling up things on the stack
+    pna.nextTick(cb, er);
+    // this can emit finish, and it will always happen
+    // after error
+    pna.nextTick(finishMaybe, stream, state);
+    stream._writableState.errorEmitted = true;
+    stream.emit('error', er);
+  } else {
+    // the caller expect this to happen before if
+    // it is async
+    cb(er);
+    stream._writableState.errorEmitted = true;
+    stream.emit('error', er);
+    // this can emit finish, but finish must
+    // always follow error
+    finishMaybe(stream, state);
+  }
+}
+
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+
+  onwriteStateUpdate(state);
+
+  if (er) onwriteError(stream, state, sync, er, cb);else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(state);
+
+    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
+      clearBuffer(stream, state);
+    }
+
+    if (sync) {
+      /*<replacement>*/
+      asyncWrite(afterWrite, stream, state, finished, cb);
+      /*</replacement>*/
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+
+function afterWrite(stream, state, finished, cb) {
+  if (!finished) onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+  var entry = state.bufferedRequest;
+
+  if (stream._writev && entry && entry.next) {
+    // Fast case, write everything using _writev()
+    var l = state.bufferedRequestCount;
+    var buffer = new Array(l);
+    var holder = state.corkedRequestsFree;
+    holder.entry = entry;
+
+    var count = 0;
+    var allBuffers = true;
+    while (entry) {
+      buffer[count] = entry;
+      if (!entry.isBuf) allBuffers = false;
+      entry = entry.next;
+      count += 1;
+    }
+    buffer.allBuffers = allBuffers;
+
+    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+    // doWrite is almost always async, defer these to save a bit of time
+    // as the hot path ends with doWrite
+    state.pendingcb++;
+    state.lastBufferedRequest = null;
+    if (holder.next) {
+      state.corkedRequestsFree = holder.next;
+      holder.next = null;
+    } else {
+      state.corkedRequestsFree = new CorkedRequest(state);
+    }
+    state.bufferedRequestCount = 0;
+  } else {
+    // Slow case, write chunks one-by-one
+    while (entry) {
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+      entry = entry.next;
+      state.bufferedRequestCount--;
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        break;
+      }
+    }
+
+    if (entry === null) state.lastBufferedRequest = null;
+  }
+
+  state.bufferedRequest = entry;
+  state.bufferProcessing = false;
+}
+
+Writable.prototype._write = function (chunk, encoding, cb) {
+  cb(new Error('_write() is not implemented'));
+};
+
+Writable.prototype._writev = null;
+
+Writable.prototype.end = function (chunk, encoding, cb) {
+  var state = this._writableState;
+
+  if (typeof chunk === 'function') {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending && !state.finished) endWritable(this, state, cb);
+};
+
+function needFinish(state) {
+  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
+}
+function callFinal(stream, state) {
+  stream._final(function (err) {
+    state.pendingcb--;
+    if (err) {
+      stream.emit('error', err);
+    }
+    state.prefinished = true;
+    stream.emit('prefinish');
+    finishMaybe(stream, state);
+  });
+}
+function prefinish(stream, state) {
+  if (!state.prefinished && !state.finalCalled) {
+    if (typeof stream._final === 'function') {
+      state.pendingcb++;
+      state.finalCalled = true;
+      pna.nextTick(callFinal, stream, state);
+    } else {
+      state.prefinished = true;
+      stream.emit('prefinish');
+    }
+  }
+}
+
+function finishMaybe(stream, state) {
+  var need = needFinish(state);
+  if (need) {
+    prefinish(stream, state);
+    if (state.pendingcb === 0) {
+      state.finished = true;
+      stream.emit('finish');
+    }
+  }
+  return need;
+}
+
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished) pna.nextTick(cb);else stream.once('finish', cb);
+  }
+  state.ended = true;
+  stream.writable = false;
+}
+
+function onCorkedFinish(corkReq, state, err) {
+  var entry = corkReq.entry;
+  corkReq.entry = null;
+  while (entry) {
+    var cb = entry.callback;
+    state.pendingcb--;
+    cb(err);
+    entry = entry.next;
+  }
+  if (state.corkedRequestsFree) {
+    state.corkedRequestsFree.next = corkReq;
+  } else {
+    state.corkedRequestsFree = corkReq;
+  }
+}
+
+Object.defineProperty(Writable.prototype, 'destroyed', {
+  get: function () {
+    if (this._writableState === undefined) {
+      return false;
+    }
+    return this._writableState.destroyed;
+  },
+  set: function (value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._writableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._writableState.destroyed = value;
+  }
+});
+
+Writable.prototype.destroy = destroyImpl.destroy;
+Writable.prototype._undestroy = destroyImpl.undestroy;
+Writable.prototype._destroy = function (err, cb) {
+  this.end();
+  cb(err);
+};
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/internal/streams/BufferList.js b/node_modules/readable-stream/lib/internal/streams/BufferList.js
new file mode 100644
index 0000000..aefc68b
--- /dev/null
+++ b/node_modules/readable-stream/lib/internal/streams/BufferList.js
@@ -0,0 +1,79 @@
+'use strict';
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+var Buffer = require('safe-buffer').Buffer;
+var util = require('util');
+
+function copyBuffer(src, target, offset) {
+  src.copy(target, offset);
+}
+
+module.exports = function () {
+  function BufferList() {
+    _classCallCheck(this, BufferList);
+
+    this.head = null;
+    this.tail = null;
+    this.length = 0;
+  }
+
+  BufferList.prototype.push = function push(v) {
+    var entry = { data: v, next: null };
+    if (this.length > 0) this.tail.next = entry;else this.head = entry;
+    this.tail = entry;
+    ++this.length;
+  };
+
+  BufferList.prototype.unshift = function unshift(v) {
+    var entry = { data: v, next: this.head };
+    if (this.length === 0) this.tail = entry;
+    this.head = entry;
+    ++this.length;
+  };
+
+  BufferList.prototype.shift = function shift() {
+    if (this.length === 0) return;
+    var ret = this.head.data;
+    if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
+    --this.length;
+    return ret;
+  };
+
+  BufferList.prototype.clear = function clear() {
+    this.head = this.tail = null;
+    this.length = 0;
+  };
+
+  BufferList.prototype.join = function join(s) {
+    if (this.length === 0) return '';
+    var p = this.head;
+    var ret = '' + p.data;
+    while (p = p.next) {
+      ret += s + p.data;
+    }return ret;
+  };
+
+  BufferList.prototype.concat = function concat(n) {
+    if (this.length === 0) return Buffer.alloc(0);
+    if (this.length === 1) return this.head.data;
+    var ret = Buffer.allocUnsafe(n >>> 0);
+    var p = this.head;
+    var i = 0;
+    while (p) {
+      copyBuffer(p.data, ret, i);
+      i += p.data.length;
+      p = p.next;
+    }
+    return ret;
+  };
+
+  return BufferList;
+}();
+
+if (util && util.inspect && util.inspect.custom) {
+  module.exports.prototype[util.inspect.custom] = function () {
+    var obj = util.inspect({ length: this.length });
+    return this.constructor.name + ' ' + obj;
+  };
+}
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/internal/streams/destroy.js b/node_modules/readable-stream/lib/internal/streams/destroy.js
new file mode 100644
index 0000000..5a0a0d8
--- /dev/null
+++ b/node_modules/readable-stream/lib/internal/streams/destroy.js
@@ -0,0 +1,74 @@
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+// undocumented cb() API, needed for core, not for public API
+function destroy(err, cb) {
+  var _this = this;
+
+  var readableDestroyed = this._readableState && this._readableState.destroyed;
+  var writableDestroyed = this._writableState && this._writableState.destroyed;
+
+  if (readableDestroyed || writableDestroyed) {
+    if (cb) {
+      cb(err);
+    } else if (err && (!this._writableState || !this._writableState.errorEmitted)) {
+      pna.nextTick(emitErrorNT, this, err);
+    }
+    return this;
+  }
+
+  // we set destroyed to true before firing error callbacks in order
+  // to make it re-entrance safe in case destroy() is called within callbacks
+
+  if (this._readableState) {
+    this._readableState.destroyed = true;
+  }
+
+  // if this is a duplex stream mark the writable part as destroyed as well
+  if (this._writableState) {
+    this._writableState.destroyed = true;
+  }
+
+  this._destroy(err || null, function (err) {
+    if (!cb && err) {
+      pna.nextTick(emitErrorNT, _this, err);
+      if (_this._writableState) {
+        _this._writableState.errorEmitted = true;
+      }
+    } else if (cb) {
+      cb(err);
+    }
+  });
+
+  return this;
+}
+
+function undestroy() {
+  if (this._readableState) {
+    this._readableState.destroyed = false;
+    this._readableState.reading = false;
+    this._readableState.ended = false;
+    this._readableState.endEmitted = false;
+  }
+
+  if (this._writableState) {
+    this._writableState.destroyed = false;
+    this._writableState.ended = false;
+    this._writableState.ending = false;
+    this._writableState.finished = false;
+    this._writableState.errorEmitted = false;
+  }
+}
+
+function emitErrorNT(self, err) {
+  self.emit('error', err);
+}
+
+module.exports = {
+  destroy: destroy,
+  undestroy: undestroy
+};
\ No newline at end of file
diff --git a/node_modules/readable-stream/lib/internal/streams/stream-browser.js b/node_modules/readable-stream/lib/internal/streams/stream-browser.js
new file mode 100644
index 0000000..9332a3f
--- /dev/null
+++ b/node_modules/readable-stream/lib/internal/streams/stream-browser.js
@@ -0,0 +1 @@
+module.exports = require('events').EventEmitter;
diff --git a/node_modules/readable-stream/lib/internal/streams/stream.js b/node_modules/readable-stream/lib/internal/streams/stream.js
new file mode 100644
index 0000000..ce2ad5b
--- /dev/null
+++ b/node_modules/readable-stream/lib/internal/streams/stream.js
@@ -0,0 +1 @@
+module.exports = require('stream');