code: public void waitForReady() {
          if (!isLoaded) {
              synchronized (LOAD_LOCK) {
                  if (!isLoaded) {
                      try {
                          long start = Runtime.getActorTime();
                          LOAD_LOCK.wait();
                          Log.d(TAG, "Waited for startup in " + (Runtime.getActorTime() - start) + " ms");
                      } catch (InterruptedException e) {
                          e.printStackTrace();
                      }
                  }
              }
          }
      }
docs: Waiting for Messenger Ready