EVNT11 — event channel buffer should generate exception when buffer beg. to overflow

The Event Service spec should be revised to include a mandatory throwing of
an exception if an Event Channel buffer begins to overflow. This exception
should be able to be caught by both the server and client applications. The
reason is that without an exception, the Event Service is making a implicit
comment on the value of an individual message. Although the Event Service
paradigm is publish/subscribe, there may be uses within that context when
the dropping of a single message is critical. Without implementing
traditional message tracking solutions such as the sequencing messages,
there is currently no way of knowing if a message has been dropped. The
throwing of an exception that can be caught, or not caught, seems to be a
reasonable solution. It would also increase the value of the services
currently provided by the Event Service.