第二个问题，因为 web 端本地是不持久化存储消息的，所以收到消息时，会把上次收到消息，到这次收到消息之间的消息都拉取，这可能会包含自己发送的消息。

demo 在上层收到消息的监听里面，会判断本地是否已存在，如果已存在的话，对消息进行更新；否则插入。

        wfc.eventEmitter.on(EventType.ReceiveMessage, (msg, hasMore) => {
//...

 // 会把下来加载更多加载的历史消息给清理了
                let lastTimestamp = 0;
                let msgListLength = conversationState.currentConversationMessageList.length;
                if (msgListLength > 0) {
                    lastTimestamp = conversationState.currentConversationMessageList[msgListLength - 1].timestamp;
                }
                this._patchMessage(msg, lastTimestamp);
                let msgIndex = conversationState.currentConversationMessageList.findIndex(m => {
                    return m.messageId === msg.messageId
                        || (gt(m.messageUid, 0) && eq(m.messageUid, msg.messageUid))
                        || (m.messageContent.type === MessageContentType.Streaming_Text_Generating
                            && (msg.messageContent.type === MessageContentType.Streaming_Text_Generating || msg.messageContent.type === MessageContentType.Streaming_Text_Generated)
                            && m.messageContent.streamId === msg.messageContent.streamId
                        )
                });
                if (msgIndex > -1) {
                    // FYI: https://v2.vuejs.org/v2/guide/reactivity#Change-Detection-Caveats
                    conversationState.currentConversationMessageList.splice(msgIndex, 1, msg);
                    console.log('msg duplicate, update message')
                    return;
                } else {
                    let firstMsg = conversationState.currentConversationMessageList[0];
                    if(firstMsg && lt(msg.timestamp, firstMsg.timestamp)) {
                        console.log('msg timestamp is less than first msg, maybe update old message content, ignore')
                        return;
                    }
                }

//...