Adding doc

docs/index.rst

@@ -33,6 +33,7 @@ Guides
    sanic/changelog
    sanic/contributing
    sanic/api_reference
+   sanic/asyncio_python37
 
 
 Module Documentation

docs/sanic/asyncio_python37.rst

@@ -0,0 +1,58 @@
+Python 3.7 AsyncIO examples
+###########################
+
+With Python 3.7 AsyncIO got major update for the following types:
+
+ - asyncio.AbstractEventLoop
+ - asyncio.AnstractServer
+
+
+This example shows how to use sanic with Python 3.7, to be precise: how to retrieve an asyncio server instance:
+
+.. code:: python
+
+    import asyncio
+    import socket
+    import os
+
+    from sanic import Sanic
+    from sanic.response import json
+
+    app = Sanic(__name__)
+
+
+    @app.route("/")
+    async def test(request):
+        return json({"hello": "world"})
+
+
+    server_socket = '/tmp/sanic.sock'
+
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+
+    try:
+        os.remote(server_socket)
+    finally:
+        sock.bind(server_socket)
+
+    if __name__ == "__main__":
+        loop = asyncio.get_event_loop()
+        srv_coro = app.create_server(
+            sock=sock,
+            return_asyncio_server=True,
+            asyncio_server_args=dict(
+                start_serving=False
+            )
+        )
+        srv = loop.run_until_complete(srv_coro)
+        try:
+            assert srv.is_serving() is False
+            loop.run_until_complete(srv.start_serving())
+            assert srv.is_serving() is True
+            loop.run_until_complete(srv.serve_forever())
+        except KeyboardInterrupt:
+            srv.close()
+            loop.close()
+
+
+Please note that uvloop does not support these features yet.