saveState method
Begins capturing the old document state for a delta-based undo. The delta is committed automatically by updateContent after the mutation, producing a minimal undo record that stores only the changed top-level nodes (50-100x smaller than a full snapshot).
Implementation
void saveState({
String description = 'Document change',
bool forceNewAction = false,
}) {
registry.dispatchSaveState(this, description);
_undoRedoManager.beginSaveState(
this,
description: description,
forceNewAction: forceNewAction,
);
}