notify method
Manually notifies all subscribers that this signal has changed.
This is typically called automatically when the value changes, but can be called manually for custom notification scenarios.
Example:
counter.notify(); // Force downstream effects to run
Implementation
@pragma("vm:prefer-inline")
@pragma("wasm:prefer-inline")
@pragma("dart2js:prefer-inline")
@override
void notify() {
assert(!isDisposed, "Signal is disposed");
notifySignal(this);
}