为什么我设置了setData，数据不更新？我使用调试工具看到AppData里也没更新？setData到底如何使用？

send方法中的this也正常的啊

send(e) {
  let msg = {};
  this.data.messageList.push(msg, { role: 'placeholder' });
  updateMsgMap(this.data.messageList);
  this.setData({
    messageList: this.data.messageList,
    title: '正在输入...'
  }, () => this.scrollToBottom());
  
  sending = true;
  request({
    method: 'POST',
    path: `xxx`,
    data: payload,
  }).then(res => {
    this.data.messageList.pop();
    const { u1, u2 } = res;
    u1.suggest = u2.content.suggestion;
    let last = this.data.messageList.pop();
    last = {...last, ...u1};
    this.data.messageList.push(last);
    if (u2.type === 'audio') {
      u2.audio_play = false;
    };
    this.data.messageList.push(u2);
    if (u2.content.isFinish) {
      this.data.messageList.push({ role: "summary" });
    }
    updateMsgMap(this.data.messageList);
    this.setData({
      messageList: this.data.messageList,
      title: 'title'
    }, () => this.scrollToBottom())
    sending = false;
  }).catch(err => {
    sending = false;
  })
},