在入栈 出栈 时界面的内存管理 会有时间差 结论得出的猜想证据是从下面打印的时间：
2016-04-13 15:24:33.028 jy_ai[17821:845029] __44-[JYKitchenViewController viewDidDisappear:]_block_invoke [Line 248] did disappear
2016-04-13 15:24:32.406 jy_ai[17821:845029] -[JY35I6MainViewController viewDidLoad] [Line 141] didLoad
2016-04-13 15:24:32.413 jy_ai[17821:845029] -[JY35I6MainViewController viewWillAppear:] [Line 110] willAppear
2016-04-13 15:24:33.026 jy_ai[17821:845029] -[JY35I6MainViewController viewDidAppear:] [Line 125] didAppear