Encourage async with ClientSession() in docs

README.rst

@@ -43,12 +43,14 @@ To retrieve something from the web:
           async with session.get(url) as response:
               return await response.text()
 
+  async def main(loop):
+      async with aiohttp.ClientSession(loop=loop) as session:
+          html = await fetch(session, 'http://python.org')
+          print(html)
+
   if __name__ == '__main__':
       loop = asyncio.get_event_loop()
-      with aiohttp.ClientSession(loop=loop) as session:
-          html = loop.run_until_complete(
-              fetch(session, 'http://python.org'))
-          print(html)
+      loop.run_until_complete(main(loop))
 
 
 Server

docs/client_reference.rst

@@ -29,9 +29,14 @@ Usage example::
              assert resp.status == 200
              return await resp.text()
 
-     with aiohttp.ClientSession() as client:
-         html = asyncio.get_event_loop().run_until_complete(fetch(client))
-         print(html)
+     async def main(loop):
+         async with aiohttp.ClientSession(loop=loop) as client:
+             html = await fetch(client)
+             print(html)
+
+     loop = asyncio.get_event_loop()
+     loop.run_until_complete(main(loop))
+
 
 .. versionadded:: 0.17
 

docs/index.rst

@@ -40,20 +40,21 @@ Getting Started
 
 Client example::
 
-    import asyncio
     import aiohttp
+    import asyncio
 
-    async def fetch_page(session, url):
+    async def fetch(session, url):
         with aiohttp.Timeout(10):
             async with session.get(url) as response:
-                assert response.status == 200
-                return await response.read()
+                return await response.text()
+
+    async def main(loop):
+        async with aiohttp.ClientSession(loop=loop) as session:
+            html = await fetch(session, 'http://python.org')
+            print(html)
 
     loop = asyncio.get_event_loop()
-    with aiohttp.ClientSession(loop=loop) as session:
-        content = loop.run_until_complete(
-            fetch_page(session, 'http://python.org'))
-        print(content)
+    loop.run_until_complete(main(loop))
 
 Server example::