code: private function getGcmJsonInner(?string $text): array
      {
          $data = $this->getAndroidJsonInner($text);
  
          $merged = $this->arrayMergeDeep($data, $this->custom, $this->gcmData ? $this->gcmData : []);
  
          // Force to be an object, because it shouldnt get encoded as [] but as {}
          if (!\count($merged)) {
              $merged = new \stdClass();
          }
  
          return $merged;
      }
docs: Gets the data part of the GCM message.