public boolean wasInvoked() {
      checkForError();
      boolean value = invoked;
      invoked = false;
      return value;
    }
Returns wether or not one of this listener methods was invoked. Before returning, the
<code>invoked</code> flag is cleared.
geode-core/src/test/java/org/apache/geode/internal/DataSerializableJUnitTest.java