SEC14 — SECIOP State Machine Discard

The SECIOP State machine has a problem with Discard context. The
specification currently specifies that if either side sends a Discard
Context, the context is discarded on both sides immediately. Therefore, a
client must wait to send a Discard context considering all messages sent
until it can figure out if all expected messages are received.

This situation causes too much coordination between the upper ORB layers
and the lower transport layers in SECIOP. The SECIOP state machine must be
knowledgeable about requests and whether they expect a repose. Then the
SECIOP message layer must know about GIOP message structures.

The proposed way to do this is when a Discard context is sent, it says
that no more data will be sent in that direction. The peer must respond in
kind with a Discard Context message when all data is sent back. Then the
context shall be closed.