docs: public synchronized boolean enableListener(boolean enable) {
          boolean success = true;
          if (enable && eventSource == null) {
              success = initEventSource();
          }
          bEnableListener = enable;
          if (tc.isDebugEnabled()) {
              Tr.debug(tc, "enableListener() cacheName=" + this.cacheName + " enable=" + enable + " success=" + success
                      + " ignoreValueInInvalidationEvent=" + this.ignoreValueInInvalidationEvent);
          }
          return success;
      }