/**
* Encode a simple UA TCP message.
*
* @param messageType {@link MessageType#Hello}, {@link MessageType#Acknowledge}, or {@link
* MessageType#Error}.
* @param messageEncoder a function that encodes the message payload.
* @param buffer the {@link ByteBuf} to encode into.
*/
private static ByteBuf encode(
MessageType messageType, Consumer<ByteBuf> messageEncoder, ByteBuf buffer)
throws UaException {
buffer.writeMedium(MessageType.toMediumInt(messageType));
buffer.writeByte('F');
int lengthIndex = buffer.writerIndex();
buffer.writeInt(0);
int indexBefore = buffer.writerIndex();
messageEncoder.accept(buffer);
int indexAfter = buffer.writerIndex();
int bytesWritten = indexAfter - indexBefore;
buffer.writerIndex(lengthIndex);
buffer.writeInt(8 + bytesWritten);
buffer.writerIndex(indexAfter);
return buffer;
}
