code: public function writeJson(IHttpResponseMessage $response, array $content): void
      {
          $json = json_encode($content);
  
          if (json_last_error() !== JSON_ERROR_NONE) {
              throw new InvalidArgumentException('Failed to JSON encode content: ' . json_last_error_msg());
          }
  
          $response->getHeaders()->add('Content-Type', 'application/json');
          $response->setBody(new StringBody($json));
      }
docs: Writes JSON to the response
  
  @param IHttpResponseMessage $response The response to write to
  @param array $content The JSON to write
  @throws InvalidArgumentException Thrown if the input JSON is incorrectly formatted
  @throws RuntimeException Thrown if the content type header's hash key could not be calculated