Class SessionFlush

object --+        
         |        
  Compound --+    
             |    
       Control --+
                 |
                SessionFlush

This control is sent by the sender of commands and handled by the
receiver of commands. It requests that the receiver produce the
indicated command sets. The receiver should issue the indicated sets
at the earliest possible opportunity.

  expected -- request notification of expected commands

  confirmed -- request notification of confirmed commands

  completed -- request notification of completed commands