Fixed async transport sleep coroutine

sdk/core/azure-core/azure/core/pipeline/transport/requests_asyncio.py

@@ -78,6 +78,9 @@ async def __aenter__(self):
     async def __aexit__(self, *exc_details):  # pylint: disable=arguments-differ
         return super(AsyncioRequestsTransport, self).__exit__()
 
+    async def sleep(self, duration):
+        await asyncio.sleep(duration)
+
     async def send(self, request: HttpRequest, **kwargs: Any) -> AsyncHttpResponse:  # type: ignore
         """Send the request using this HTTP sender.
 

sdk/core/azure-core/azure/core/pipeline/transport/requests_trio.py

@@ -143,7 +143,7 @@ async def __aexit__(self, *exc_details):  # pylint: disable=arguments-differ
         return super(TrioRequestsTransport, self).__exit__()
 
     async def sleep(self, duration):
-        await trio.sleep(duration)
+        return super(TrioRequestsTransport, self).sleep(duration)
 
     async def send(self, request: HttpRequest, **kwargs: Any) -> AsyncHttpResponse:  # type: ignore
         """Send the request using this HTTP sender.

sdk/core/azure-core/tests/azure_core_asynctests/test_pipeline.py

@@ -119,6 +119,18 @@ async def test_basic_async_requests():
 
     assert response.http_response.status_code == 200
 
+@pytest.mark.asyncio
+async def test_async_transport_sleep():
+
+    async with AsyncioRequestsTransport() as transport:
+        await transport.sleep(1)
+
+    async with AioHttpTransport() as transport:
+        await transport.sleep(1)
+
+    async with TrioRequestsTransport() as transport:
+        await transport.sleep(1)
+
 @pytest.mark.asyncio
 async def test_conf_async_requests():