chore(sinks): delay embedded sinks disposal (#26)

Refactor all composite sinks in the library to delay the disposal of
their embedded sinks. All embedded sinks will now be disposed of when
their parent sink is disposed of.

src/sghi/etl/commons/sinks.py

@@ -99,7 +99,7 @@ def sink(f: Callable[[_PDT], None]) -> Sink[_PDT]:
 class NullSink(Sink[_PDT], Generic[_PDT]):
     """A :class:`Sink` that discards all the data it receives.
 
-    Like to ``dev/null`` on Unix, instances of this ``Sink`` discard all data
+    Like ``dev/null`` on Unix, instances of this ``Sink`` discard all data
     drained to them but report the drain operation as successful. This is
     mostly useful as a placeholder or where further consumption of processed
     data is not required.
@@ -190,7 +190,7 @@ class ScatterSink(Sink[_PDT], Generic[_PDT]):
     Disposing instances of this class also disposes of their embedded sinks.
 
     .. admonition:: Regarding retry safety
-        :class: tip
+        :class: caution
 
         Instances of this ``Sink`` are **NOT SAFE** to retry.
     """
@@ -324,8 +324,8 @@ def drain(self, processed_data: _PDT) -> None:
         """
         self._logger.info("Draining processed data to all available sinks.")
 
-        with self._executor as executor:
-            futures = executor.execute(processed_data)
+        executor = self._executor.__enter__()
+        futures = executor.execute(processed_data)
 
         self._result_gatherer(futures)
 
@@ -357,9 +357,9 @@ def dispose(self) -> None:
     def _sink_to_task(self, s: Sink[_PDT]) -> Task[_PDT, None]:
         @task
         def do_drain(processed_data: _PDT) -> None:
-            with s as _s:
-                drain = self._retry_policy_factory().retry(_s.drain)
-                return drain(processed_data)
+            _s = s.__enter__()
+            drain = self._retry_policy_factory().retry(_s.drain)
+            return drain(processed_data)
 
         return do_drain
 
@@ -390,7 +390,7 @@ class SplitSink(Sink[Sequence[_PDT]], Generic[_PDT]):
     Disposing instances of this class also disposes of their embedded sinks.
 
     .. admonition:: Regarding retry safety
-        :class: tip
+        :class: caution
 
         Instances of this ``Sink`` are **NOT SAFE** to retry.
     """  # noqa: D205
@@ -550,8 +550,8 @@ def drain(self, processed_data: Sequence[_PDT]) -> None:
             "to all available sinks."
         )
 
-        with self._executor as executor:
-            futures = executor.execute(processed_data)
+        executor = self._executor.__enter__()
+        futures = executor.execute(processed_data)
 
         self._result_gatherer(futures)
 
@@ -587,9 +587,9 @@ def _sink_to_task(
     ) -> Task[Sequence[_PDT], None]:
         @task
         def do_drain(processed_data: Sequence[_PDT]) -> None:
-            with s as _s:
-                drain = self._retry_policy_factory().retry(_s.drain)
-                return drain(processed_data[i])
+            _s = s.__enter__()
+            drain = self._retry_policy_factory().retry(_s.drain)
+            return drain(processed_data[i])
 
         return do_drain