docs: public void adjustPoolSize(int newPoolSize) {
          if (newPoolSize != poolSize) {
              poolSize = newPoolSize;
              if (executor instanceof ThreadPoolExecutor) {
                  ThreadPoolExecutor pool = (ThreadPoolExecutor) executor;
                  pool.setCorePoolSize(newPoolSize);
                  pool.setMaximumPoolSize(newPoolSize);
              }
          }
      }