/**
  * Check whether to hydrate on a key.
  *
  * @param Request $request
  * @param string $key
  * @return bool
  */
 public function shouldHydrate(Request $request, $key)
 {
     if ($request->getOperation() === Request::UPDATE && $request->isPartial()) {
         // Conditionally hydrate on partial_update operation.
         return array_key_exists($key, $request->getContent());
     }
     // Always hydrate on create and update operations.
     return true;
 }