code: func NewStream(cfg API, out io.Writer, bufSize int) *Stream {
  	return &Stream{
  		cfg:       cfg.(*frozenConfig),
  		out:       out,
  		buf:       make([]byte, 0, bufSize),
  		Error:     nil,
  		indention: 0,
  	}
  }
docs: // NewStream create new stream instance.
  // cfg can be jsoniter.ConfigDefault.
  // out can be nil if write to internal buffer.
  // bufSize is the initial size for the internal buffer in bytes.