Use distributed's version of this util.

distributed/actor.py

@@ -1,12 +1,11 @@
 import asyncio
 import functools
-from inspect import iscoroutinefunction
 import threading
 from queue import Queue
 
 from .client import Future, default_client
 from .protocol import to_serialize
-from .utils import thread_state, sync
+from .utils import iscoroutinefunction, thread_state, sync
 from .utils_comm import WrappedKey
 from .worker import get_worker