type Message tags is different from facebook event #868

export type Message = {
  mid: string;
  isEcho?: boolean;
  text?: string;
  stickerId?: number;
  quickReply?: QuickReply;
  attachments?: Attachment[];
  tags?: Tag; // should be Tag rather than Tag[]
  replyTo?: ReplyTo;
  appId?: number;
  metadata?: string;
};