***************************************************** /*                   Blob constructor *****************************************************
function Blob(chunks, opts) {
      chunks = chunks || []
      for (var i = 0, len = chunks.length; i < len; i++) {
        var chunk = chunks[i]
        if (chunk instanceof Blob) {
          chunks[i] = chunk._buffer
        } else if (typeof chunk === 'string') {
          chunks[i] = toUTF8Array(chunk)
        } else if (arrayBufferSupported && (ArrayBuffer.prototype.isPrototypeOf(chunk) || isArrayBufferView(chunk))) {
          chunks[i] = bufferClone(chunk)
        } else if (arrayBufferSupported && isDataView(chunk)) {
          chunks[i] = bufferClone(chunk.buffer)
        } else {
          chunks[i] = toUTF8Array(String(chunk))
        }
      }

      this._buffer = [].concat.apply([], chunks)
      this.size = this._buffer.length
      this.type = opts ? opts.type || '' : ''
    }