code: protected function onUserError(Event $error)
      {
          switch ($this->cfg['onEUserError']) {
              case 'continue':
                  $error['continueToNormal'] = false;
                  break;
              case 'log':
                  // log the error, but continue script
                  if (!$error->isPropagationStopped() && $error['continueToNormal']) {
                      $this->log($error);
                  }
                  $error['continueToNormal'] = false;
                  break;
              case 'normal':
                  // force continueToNormal
                  $error['continueToNormal'] = true;
                  break;
              default:
                  /*
                      no special consideration
                      unless errorHandler.error subscriber changes `continueToNormal` value,
                      script will be halted
                  */
          }
      }
docs: Handle E_USER_ERROR
  
  Should script terminate, or continue?
  
  @param Event $error errorHandler.error event
  
  @return void