code: func (s *framedDecoderStream) isValidByteSequence(p []byte) bool {
  	for _, b := range p {
  		if !s.params.Encoding.IsValidByte(b) {
  			return false
  		}
  	}
  	return true
  }
docs: // isValidByteSequence checks if the byte sequence is valid as far as our
  // underlying encoder is concerned.