code: protected function setState(ShipmentSubjectInterface $subject, $state)
      {
          if ($state !== $subject->getShipmentState()) {
              $subject->setShipmentState($state);
  
              return true;
          }
  
          return false;
      }
docs: Sets the shipment state.
  
  @param ShipmentSubjectInterface $subject
  @param string                   $state
  
  @return bool Whether the shipment state has been updated.