in ffwd-client/src/main/java/com/spotify/ffwd/FastForward.java [114:130]
void sendFrame(byte[] bytes, Version v) throws IOException {
final ByteBuffer buffer = ByteBuffer.allocate(bytes.length + 8);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putInt(v.getVersion());
buffer.putInt(buffer.capacity());
buffer.put(bytes);
buffer.rewind();
final byte[] send = new byte[buffer.capacity()];
buffer.get(send);
final DatagramPacket packet = new DatagramPacket(send, send.length,
addr, port);
socket.send(packet);
}