public Collection<DiagnosticsExceptionEvent> getExceptionEvents() {
    return (Collection<DiagnosticsExceptionEvent>) getFromMetricsMessage(SAMZACONTAINER_METRICS_GROUP_NAME,
        EXCEPTION_LIST_METRIC_NAME);
  }
Check if the message has no contents.
@return True if the message is empty, false otherwise.
samza-core/src/main/scala/org/apache/samza/diagnostics/DiagnosticsStreamMessage.java