Update design doc

[dingweiqings]

Description

After I read your good code and try to understand your design , I add some notes in your design md doc and fix some typos. This PR is for this .

Change File

并发模型.md

[hbzzhtt]

You've added too many redundant files, like CMakeFiles , Makefile, xxx.log .....

[wk-night]

请问一下能给HttpData文件解释一下吗，有些搞不明白这个文件的作用