wip (+5 squashed commits)

Squashed commits:
[53c6c53] wip
[66f482c] wip
[b003315] wip
[f6f9d9e] wip
[4c95c7b] wip

examples/heart_rate_server.py

@@ -29,6 +29,7 @@ from bumble.device import Device
 from bumble.transport import open_transport_or_link
 from bumble.profiles.device_information_service import DeviceInformationService
 from bumble.profiles.heart_rate_service import HeartRateService
+from bumble.utils import AsyncRunner
 
 
 # -----------------------------------------------------------------------------
@@ -98,6 +99,17 @@ async def main():
             )
         )
 
+        # Notify subscribers of the current value as soon as they subscribe
+        @heart_rate_service.heart_rate_measurement_characteristic.on('subscription')
+        def on_subscription(connection, notify_enabled, indicate_enabled):
+            if notify_enabled or indicate_enabled:
+                AsyncRunner.spawn(
+                    device.notify_subscriber(
+                        connection,
+                        heart_rate_service.heart_rate_measurement_characteristic
+                    )
+                )
+
         # Go!
         await device.power_on()
         await device.start_advertising(auto_restart=True)