Question regarding update of reader/writer indexes of ByteBuf in our client API

**QUESTION**

Regarding the updates to readerIndex/writerIndex of ByteBuf by API method, AFAIU if the API method is doing read operation from the ByteBuf then after calling API method with ByteBuf argument, I wouldn’t expect the readerIndex of the ByteBuf to be at 0.

I mean

```
myApplicationMethod() {

ByteBuf byteBuf = createNewInstanceOfByteBuf();
// add data to byteBuf
APIClass.APIReadMethod(bytebuf);
// here I would expect the readerIndex and writerIndex of byteBuf to be the same,
// since APIReadMethod has consumed/read all of the data in the byteBuf
}
```
But in our case, WriteAdvHandle.write(long entryId, ByteBuf data) doesn’t advances readerIndex of data ByteBuf and this might be because of the following clone https://github.com/apache/bookkeeper/blob/19846b23de3be13e28082d4ba73e21bb8fa39ad2/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/BookieProtocol.java#L271

I would expect it to behave in the same way as other core java APIs deal with ByteBuffer - for eg: https://docs.oracle.com/javase/7/docs/api/java/nio/channels/FileChannel.html#read(java.nio.ByteBuffer) https://netty.io/4.0/api/io/netty/buffer/ByteBuf.html#readBytes-io.netty.buffer.ByteBuf- here position of ByteBuffer and readerIndex of ByteBuf is advanced.

**Que:** Are we following general practices of Buffers with our API? Have we mentioned the expected behavior in detail in our API docs?