code: public List<Executor> getAllExecutors() {
          List<Executor> result = new ArrayList<>(executors.size() + oneOffExecutors.size());
          result.addAll(executors);
          result.addAll(oneOffExecutors);
          return result;
      }
docs: Gets the read-only snapshot view of all {@link Executor} instances including {@linkplain OneOffExecutor}s.
  
  @return the read-only snapshot view of all {@link Executor} instances including {@linkplain OneOffExecutor}s.
  @since 2.55