hasCheckedState constant Null safety
The semantics node has the quality of either being "checked" or "unchecked".
This flag is mutually exclusive with hasToggledState.
For example, a checkbox or a radio button widget has checked state.
- SemanticsFlag.isChecked, which controls whether the node is "checked" or "unchecked".
static const SemanticsFlag hasCheckedState = SemanticsFlag._(_kHasCheckedStateIndex);