NavEntryDecorator

the callback to clean up the decorator state associated with a NavEntry.contentKey when the last NavEntry with that contentKey has been popped from the backStack. It provides the NavEntry.contentKey of the popped entry as input. This callback is invoked if and only if all these conditions are met: 1. A NavEntry has been popped from the backStack 2. The NavEntry that has been popped is the last entry on the backStack with that particular NavEntry.contentKey 3. The NavEntry.content of the popped NavEntry has left composition

the composable function to decorate a NavEntry. Note that this function only gets invoked for NavEntries that are actually getting rendered (i.e. by invoking the NavEntry.content.)

the type of the backStack key