document the need to monkey patch with eventlet and gevent

Author: miguelgrinberg

docs/index.rst

@@ -276,7 +276,6 @@ through the ``RedisManager`` class. This class takes the same arguments as
 ``KombuManager``, but connects directly to a Redis store using the queue's
 pub/sub functionality::
 
-
     mgr = socketio.RedisManager('redis://')
     sio = socketio.Server(client_manager=mgr)
 
@@ -294,6 +293,11 @@ of a listening thread. For example::
     # emit an event
     redis.emit('my event', data={'foo': 'bar'}, room='my room')
 
+Note: when using a third party package to manage a message queue such as Redis
+or RabbitMQ in conjunction with eventlet or gevent, it is necessary to monkey
+patch the Python standard library, so that these packages access coroutine
+friendly library functions and classes.
+
 Deployment
 ----------