channel was not properly initialized in several pubsub client managers (#1476)

src/socketio/async_aiopika_manager.py

@@ -43,12 +43,12 @@ class AsyncAioPikaManager(AsyncPubSubManager):  # pragma: no cover
             raise RuntimeError('aio_pika package is not installed '
                                '(Run "pip install aio_pika" in your '
                                'virtualenv).')
+        super().__init__(channel=channel, write_only=write_only, logger=logger)
         self.url = url
         self._lock = asyncio.Lock()
         self.publisher_connection = None
         self.publisher_channel = None
         self.publisher_exchange = None
-        super().__init__(channel=channel, write_only=write_only, logger=logger)
 
     async def _connection(self):
         return await aio_pika.connect_robust(self.url)

src/socketio/async_redis_manager.py

@@ -52,10 +52,10 @@ class AsyncRedisManager(AsyncPubSubManager):  # pragma: no cover
                                '(Run "pip install redis" in your virtualenv).')
         if not hasattr(aioredis.Redis, 'from_url'):
             raise RuntimeError('Version 2 of aioredis package is required.')
+        super().__init__(channel=channel, write_only=write_only, logger=logger)
         self.redis_url = url
         self.redis_options = redis_options or {}
         self._redis_connect()
-        super().__init__(channel=channel, write_only=write_only, logger=logger)
 
     def _redis_connect(self):
         if not self.redis_url.startswith('redis+sentinel://'):

src/socketio/redis_manager.py

@@ -75,10 +75,10 @@ class RedisManager(PubSubManager):  # pragma: no cover
             raise RuntimeError('Redis package is not installed '
                                '(Run "pip install redis" in your '
                                'virtualenv).')
+        super().__init__(channel=channel, write_only=write_only, logger=logger)
         self.redis_url = url
         self.redis_options = redis_options or {}
         self._redis_connect()
-        super().__init__(channel=channel, write_only=write_only, logger=logger)
 
     def initialize(self):
         super().initialize()

src/socketio/zmq_manager.py

@@ -57,6 +57,7 @@ class ZmqManager(PubSubManager):  # pragma: no cover
         if not (url.startswith('zmq+tcp://') and r.search(url)):
             raise RuntimeError('unexpected connection string: ' + url)
 
+        super().__init__(channel=channel, write_only=write_only, logger=logger)
         url = url.replace('zmq+', '')
         (sink_url, sub_port) = url.split('+')
         sink_port = sink_url.split(':')[-1]
@@ -72,7 +73,6 @@ class ZmqManager(PubSubManager):  # pragma: no cover
         self.sink = sink
         self.sub = sub
         self.channel = channel
-        super().__init__(channel=channel, write_only=write_only, logger=logger)
 
     def _publish(self, data):
         pickled_data = pickle.dumps(