Add a stop method for ComponentMetricFetcher

This should close the raw data receiver when the fetcher is no longer
needed.

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/sdk/timeseries/battery_pool/_component_metric_fetcher.py

@@ -21,6 +21,7 @@
     ComponentMetricId,
     InverterData,
 )
+from typing_extensions import override
 
 from ..._internal._asyncio import AsyncConstructible
 from ..._internal._constants import MAX_BATTERY_DATA_AGE_SEC
@@ -68,6 +69,10 @@ async def async_new(
     async def fetch_next(self) -> ComponentMetricsData | None:
         """Fetch metrics for this component."""
 
+    @abstractmethod
+    def stop(self) -> None:
+        """Stop the metric fetcher."""
+
 
 class LatestMetricsFetcher(ComponentMetricFetcher, Generic[T], ABC):
     """Subscribe for the latest component data and extract the needed metrics."""
@@ -143,6 +148,11 @@ async def fetch_next(self) -> ComponentMetricsData | None:
 
         return ComponentMetricsData(self._component_id, data.timestamp, metrics)
 
+    @override
+    def stop(self) -> None:
+        """Stop the metric fetcher."""
+        self._receiver.close()
+
     @abstractmethod
     def _extract_metric(self, data: T, mid: ComponentMetricId) -> float: ...