@Override
        public String getMessage() {
            if (markAsProcessedOnGetMessage) markAsProcessed();
            return super.getMessage();
        }
In some tests, we want to ensure that a thrown exception has been handled by the framework before
we do something else. There is no official hook to receive notification that the framework has
handled an exception, but we assume (actually know) that the message of the exception will be
accessed to create an error message. The provided event will signal that the exception
has been _looked at_ by the framework, which we treat as synonymous with "handled" (due to
synchronization in the framework, it is).
jdisc_core/src/main/java/com/yahoo/jdisc/test/ServerProviderConformanceTest.java