@NotNull
    public static <X> Processor<? super X> combine(@NotNull Processor<? super X> processor1, @Nullable Processor<? super X> processor2) {
      return processor2 == null ? processor1 : new CompositeProcessor<>(processor1, processor2);
    }
@NotNull
    public static <X> Processor<? super X> combine(@NotNull Processor<? super X> processor1, @Nullable Processor<? super X> processor2)