code: public function registerRead(LoopInterface $loop, callable $listener, $once = false)
      {
          if ($once) {
              $listener2 = function ($worker, $loop) use ($listener) {
                  $this->unregisterRead($loop);
                  call_user_func($listener, $worker, $loop);
              };
              foreach ($this->workers as $worker) {
                  Selectable::registerRead($loop, $worker, $listener2);
              }
          } else {
              foreach ($this->workers as $worker) {
                  Selectable::registerRead($loop, $worker, $listener);
              }
          }
  
          return $this;
      }
docs: @param LoopInterface $loop
  @param callable      $listener
  @param bool          $once
  
  @return $this