untilChanged method
Waits until the value changes from its current value.
Completes with the new value when it changes. Uses != for comparison.
Example:
final status = Signal('idle');
status.value = 'loading';
final next = await status.untilChanged(); // Waits for status != 'loading'
Implementation
Until<T> untilChanged({bool? detach}) =>
Until<T>.changed(this, detach: detach);