code: function Buf(buffer) {
    this._initialSize = 64 * 1024;
    this._stepSize = this._initialSize;
    this._pos = 0;
  
    if (typeof buffer === 'number') {
      this._initialSize = buffer;
    }
    if (buffer instanceof Buffer) {
      this._buf = buffer;
    } else {
      this._buf = new Buffer(this._initialSize);
    }
  }
docs: Helper class to read and write from Buffer object.
  
  @constructor