sock: code cleanup.
sock: code formatting.
sock: avoid trying to ack RMA_READ_REPLY messages.
sock: code cleanup
+ make sure we control the number of in-flight messages for RMA read.
sock: Avoid handling piggyback acks twice in the context of RMA read.
+ stop releasing RX buffer early on when the ACK is piggyacked (data from the buffer still needed)
+ code clean-up