do not rely on asnycio

Author: maxfischer2781

asyncstdlib/asynctools.py

@@ -1,5 +1,5 @@
-from asyncio import iscoroutinefunction
 from functools import wraps
+from inspect import iscoroutinefunction
 from typing import (
     Union,
     AsyncContextManager,

asyncstdlib/functools.py

@@ -1,4 +1,4 @@
-from asyncio import iscoroutinefunction
+from inspect import iscoroutinefunction
 from typing import (
     Callable,
     Awaitable,