code: func ParseCloseFrameDataUnsafe(payload []byte) (code StatusCode, reason string) {
  	if len(payload) < 2 {
  		return
  	}
  	code = StatusCode(binary.BigEndian.Uint16(payload))
  	reason = btsToString(payload[2:])
  	return
  }
docs: // ParseCloseFrameDataUnsafe is like ParseCloseFrameData except the thing
  // that it does not copies payload bytes into reason, but prepares unsafe cast.