活动图
http://v3.processon.com/chart_image/59000f49e4b09b2de51ead33.png
时序图
http://v3.processon.com/chart_image/59003304e4b0af9ce9b4008b.png
http://v3.processon.com/chart_image/590038aee4b0af9ce9b402fe.png