static fromRequest(request, scope, action, result) {
    return new DocumentNotification({
      action,
      collection: request.input.resource.collection,
      controller: request.input.controller,
      index: request.input.resource.index,
      node: global.kuzzle.id,
      protocol: request.context.connection.protocol,
      requestId: request.id,
      result,
      scope,
      status: 200,
      timestamp: request.timestamp,
      volatile: request.input.volatile,
    });
  }
Instantiates a DocumentNotification object from a KuzzleRequest

@param {Request} request - the request object from which the notification is issued
@param {string} scope - The scope of the notification (in or out)
@param {state} state - The document state (pending or done)
@param {action} action - Action performed on the document
@param {result} content - Notification content
@returns {DocumentNotification}