serious memory leak in iOS platform

[spirit-jsb]

On iOS, we can't call the detachChild method properly when we swipe to close the page, which causes a serious memory leak, is there any way to solve this problem

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[programming086]

@rudro do you have an answer?

[alexvbush]

@spirit-jsb this should probably help #131 (comment)

[alexvbush]

alternative is to override leftBarButtonItem and only allow an explicit back button action where you cna route away from child. that way you can avoid memory leaks