code: @TargetApi(Build.VERSION_CODES.HONEYCOMB)
      public static RxLoaderManager get(Activity activity) {
          if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB) {
              throw new UnsupportedOperationException("Method only valid in api 11 and above, use RxLoaderManagerCompat to support older versions (requires support library)");
          }
  
          RxLoaderBackendFragment manager = (RxLoaderBackendFragment) activity.getFragmentManager().findFragmentByTag(FRAGMENT_TAG);
          if (manager == null) {
              manager = new RxLoaderBackendFragment();
              activity.getFragmentManager().beginTransaction().add(manager, FRAGMENT_TAG).commit();
          }
          return new RxLoaderManager(manager);
      }
docs: Get an instance of the {@code RxLoaderManager} that is tied to the lifecycle of the given
  {@link android.app.Activity}. If you are using the support library, then you should use
  {@link me.tatarka.rxloader.RxLoaderManagerCompat#get(android.support.v4.app.FragmentActivity)}
  instead.
  
  @param activity the activity
  @return the {@code RxLoaderManager}