asyncio: Support PEP 492. Issue #24017.
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index 74a99ba..d06828a 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -19,6 +19,7 @@
 _FINISHED = 'FINISHED'
 
 _PY34 = sys.version_info >= (3, 4)
+_PY35 = sys.version_info >= (3, 5)
 
 Error = concurrent.futures._base.Error
 CancelledError = concurrent.futures.CancelledError
@@ -387,6 +388,9 @@
         assert self.done(), "yield from wasn't used with future"
         return self.result()  # May raise too.
 
+    if _PY35:
+        __await__ = __iter__ # make compatible with 'await' expression
+
 
 def wrap_future(fut, *, loop=None):
     """Wrap concurrent.futures.Future object."""