Install the asyncio reactor on "import scrapy".

scrapy/__init__.py

@@ -23,6 +23,28 @@ import warnings
 warnings.filterwarnings('ignore', category=DeprecationWarning, module='twisted')
 del warnings
 
+# Install twisted asyncio loop
+def _install_asyncio_reactor():
+    global asyncio_supported
+    try:
+        import asyncio
+        from twisted.internet import asyncioreactor
+    except ImportError:
+        pass
+    else:
+        from twisted.internet.error import ReactorAlreadyInstalledError
+        try:
+            asyncioreactor.install(asyncio.get_event_loop())
+            asyncio_supported = True
+        except ReactorAlreadyInstalledError:
+            import twisted.internet.reactor
+            if isinstance(twisted.internet.reactor,
+                              asyncioreactor.AsyncioSelectorReactor):
+                asyncio_supported = True
+asyncio_supported = False
+_install_asyncio_reactor()
+del _install_asyncio_reactor
+
 # Apply monkey patches to fix issues in external libraries
 from . import _monkeypatches
 del _monkeypatches