protected Toolbar onCreateToolbar() {
        return new Toolbar(getContext());
    }
Provide an opportunity to start asynchronous tasks<p>
If we perform an asynchronous task in onViewCreated and the task is completed before
the animation completes. At this point, the padding data triggers the re-measure
and causes an animation exception.<p>

Callback when the fragment animation ends, later than onViewCreated

@param container
pandora-core/src/main/java/tech/linjiang/pandora/ui/fragment/BaseFragment.java