Possible logic error in ClientCnxnSocketNIO

[Robin]

Hi,
When SASL authentication is enabled, the ZooKeeper client will finally call 
ClientCnxnSocketNIO#sendPacket(Packet p) to send a packet to server:
@Override
void sendPacket(Packet p) throws IOException {
    SocketChannel sock = (SocketChannel) sockKey.channel();
    if (sock == null) {
        throw new IOException("Socket is null!");
    }
    p.createBB();
    ByteBuffer pbb = p.bb;
    sock.write(pbb);
}

One problem I can see is that the sock is non-blocking, so when the sock's 
output buffer is full(theoretically), only part of the Packet is sent out and 
the communication will break.

Thanks,
- Robin