Keeping the state of the subtree is potentially expensive (because it means all the objects are still in memory; their resources are not released). It should only be maintained if it cannot be recreated on demand. One example of when the state would be maintained is if the child subtree contains a Navigator, since that widget maintains elaborate state that cannot be recreated on the fly.
If this property is false, then maintainAnimation must also be false.
final bool maintainState