*     {@code get()} throws a different kind of exception, that exception itself.
   * @param executor the executor that runs {@code fallback} if {@code input} fails
   * @since 19.0
   */
  @J2ktIncompatible
  @Partially.GwtIncompatible("AVAILABLE but requires exceptionType to be Throwable.class")
  public static <V extends @Nullable Object, X extends Throwable> ListenableFuture<V> catching(
      ListenableFuture<? extends V> input,