@Override
public int read(byte[] b, int off, int len) throws IOException {
  if (message != null) {
    int size = message.getSerializedSize();
    if (size == 0) {
      message = null;
      partial = null;
      return -1;
    }
    if (len >= size) {
      // This is the only case that is zero-copy.
      CodedOutputByteBufferNano output = CodedOutputByteBufferNano.newInstance(b, off, size);
      message.writeTo(output);
      output.checkNoSpaceLeft();

      message = null;
      partial = null;
      return size;
    }

    toPartial();
  }
  if (partial != null) {
    return partial.read(b, off, len);
  }
  return -1;
}
 

@Override
protected void encode(
        ChannelHandlerContext ctx, MessageNano msg, List<Object> out) throws Exception {
    final int size = msg.getSerializedSize();
    final ByteBuf buffer = ctx.alloc().heapBuffer(size, size);
    final byte[] array = buffer.array();
    CodedOutputByteBufferNano cobbn = CodedOutputByteBufferNano.newInstance(array,
            buffer.arrayOffset(), buffer.capacity());
    msg.writeTo(cobbn);
    buffer.writerIndex(size);
    out.add(buffer);
}
 

@NonNull
public static byte[] toByteArray(@NonNull final MessageNano messageNano) throws IOException {
    final byte[] output = new byte[messageNano.getSerializedSize()];
    messageNano.writeTo(CodedOutputByteBufferNano.newInstance(output));
    return output;
}