Upload multiple attachments may send them in random orders

Using DirectLineJS (not Web Chat) and send the following to the bot.

directLine.postActivity({
  attachments: [{
    contentType: 'image/png',
    contentUrl: 'https://webchat-waterbottle.azurewebsites.net/public/surfacelogo.png'
  }, {
    contentType: 'image/png',
    contentUrl: 'https://webchat-waterbottle.azurewebsites.net/public/xboxlogo.png'
  }],
  text: 'Hello, World!',
  type: 'message'
});

Due to network load speed differ, the bot may receive the two attachments in reversed order.

I looked at network trace, it seems DLJS is the root cause, not the channel.

从 DirectLineJS 的 postActivity 入口开始，在观察网络跟踪的同时复现包含两个图像附件的示例。跟踪附件上传和活动发送流程；完成标准是 bot 按照与输入数组相同的顺序接收附件。