code: public ServerBuilder blockingTaskExecutor(Executor blockingTaskExecutor, boolean shutdownOnStop) {
          this.blockingTaskExecutor = requireNonNull(blockingTaskExecutor, "blockingTaskExecutor");
          shutdownBlockingTaskExecutorOnStop = shutdownOnStop;
          return this;
      }
docs: Sets the {@link Executor} dedicated to the execution of blocking tasks or invocations.
  If not set, {@linkplain CommonPools#blockingTaskExecutor() the common pool} is used.
  
  @param shutdownOnStop whether to shut down the {@link Executor} when the {@link Server} stops