[Gray Watson]

The http://www.nabble.com/file/p15994217/UNICAST.java.patch patch to
UNICAST.java adds an "immediate_ack" boolean to the UNICAST protocol which
causes it to return the ACK to the client before processing it. UNICAST,
by design, only allows one packet up the stack per sender at any time. We
had some flow control issues earlier and this was one of the mechanisms we
used to alleviate the retransmit cycles where packets would be retransmitted
4-5 times even though many had already been received by the received – just
not ACK'd.