In current implementation, Netconf session send subsequent rpc messages to device
before receiving previous rpc reply, the session will queue the message for acknowledgement of reply message.

Some device may discard subsequent messages before current message is processed over. thus will cause the message in queue never get the reply. and can't guarantee the message process pipeline in the device.

my recommendation is this:

Netconf session queue all the messages to be sent and send the first message in queue to device, after receiving the reply message ,dequeue the message and get the next message and send to device.

Thanks.