code: @SuppressWarnings("unchecked")
    public S handleIf(BiPredicate<R, ? extends Throwable> resultPredicate) {
      Assert.notNull(resultPredicate, "resultPredicate");
      failuresChecked = true;
      failureConditions.add((BiPredicate<R, Throwable>) resultPredicate);
      return (S) this;
    }
docs: Specifies that a failure has occurred if the {@code resultPredicate} matches the execution result.
  
  @throws NullPointerException if {@code resultPredicate} is null