code: func NewFrame(op OpCode, fin bool, p []byte) Frame {
  	return Frame{
  		Header: Header{
  			Fin:    fin,
  			OpCode: op,
  			Length: int64(len(p)),
  		},
  		Payload: p,
  	}
  }
docs: // NewFrame creates frame with given operation code,
  // flag of completeness and payload bytes.