protected String formatMessage(final String msgPattern, final String[] sArgs) {
    return format(msgPattern, sArgs);
  }
Returns the Throwable that was given as the last argument, if any. It will not survive
serialization. The Throwable exists as part of the message primarily so that it can be
extracted from the end of the list of parameters and then be added to the LogEvent. As such,
the Throwable in the event should not be used once the LogEvent has been constructed.

@return the Throwable, if any.
geode-logging/src/main/java/org/apache/geode/logging/internal/log4j/api/message/GemFireParameterizedMessage.java