maintainSemantics property
Whether to maintain the semantics for the sliver when it is hidden (e.g. for accessibility).
To set this, maintainSize must also be set.
By default, with maintainSemantics set to false, the sliver is not
visible to accessibility tools when it is hidden from the user. If this
flag is set to true, then accessibility tools will report the widget as if
it was present.
Dynamically changing this value may cause the current state of the subtree to be lost (and a new instance of the subtree, with new State objects, to be immediately created if visible is true).
Implementation
final bool maintainSemantics;