Update spawn_blinking_led_task()

src/output/blinking_led_task.rs

@@ -24,11 +24,19 @@ pub fn blinking_led_task(
     }
 }
 
+/// Spawn a task that periodically emits a blinking LED trigger.
+///
+/// Needed to synchronize the frequencies of all blinking LEDs.
+///
+/// Returns a subscriber for receiving update triggers. The initial
+/// update is available immediately and emitted as a change notification.
 #[cfg(feature = "blinking-led-task-tokio-rt")]
 #[must_use]
 pub fn spawn_blinking_led_task(period: Duration) -> discro::Subscriber<BlinkingLedOutput> {
     let publisher = Publisher::new(BlinkingLedOutput::ON);
-    let subscriber = publisher.subscribe();
+    // Mark the subscriber as changed on subscription for emitting
+    // an initial change notification immediately.
+    let subscriber = publisher.subscribe_changed();
     let task = blinking_led_task(period, publisher);
     tokio::spawn(task);
     subscriber