Function WriteMessage

server/wire/protocol.go:187–207

writeMessage writes a message to the client

(w io.Writer, msgType byte, data []byte)

	if length < 4 || length > maxMessageLength {
		return 0, nil, fmt.Errorf("invalid message length: %d", length)
	}

	// Read message body
	body := make([]byte, length-4)
	if length > 4 {
		if _, err := io.ReadFull(r, body); err != nil {
			return 0, nil, fmt.Errorf("failed to read message body: %w", err)
		}
	}

	return msgType, body, nil
}

// writeMessage writes a message to the client
func WriteMessage(w io.Writer, msgType byte, data []byte) error {
	// Write message type
	if _, err := w.Write([]byte{msgType}); err != nil {
		return err
	}

	// Write length (includes itself, 4 bytes)
	length := int32(len(data) + 4)
	if err := binary.Write(w, binary.BigEndian, length); err != nil {
		return err