code: func (stream *Stream) WriteInt16(nval int16) {
  	var val uint16
  	if nval < 0 {
  		val = uint16(-nval)
  		stream.buf = append(stream.buf, '-')
  	} else {
  		val = uint16(nval)
  	}
  	stream.WriteUint16(val)
  }
docs: // WriteInt16 write int16 to stream