code: public Trigger<? super S> getLoadTrigger() {
          ForLoad<S> forLoad = mForLoad;
          return forLoad.isEmpty() ? null : forLoad;
      }
docs: Returns a consolidated trigger to call for load operations, or null if
  none. If not null, the consolidated trigger is not a snapshot -- it will
  change as the set of triggers in this manager changes.
  
  @since 1.2