Change default close code to 4000 instead of 1000.

This prevents our sessions from being invalidated by Discord which
caused a lot of failures when resuming. This caused an unnecessary
amount of IDENTIFYs to happen depending on the circumstances.

Closes #2631

See also discord/discord-api-docs#1472

discord/client.py

@@ -549,7 +549,7 @@ class Client:
                 pass
 
         if self.ws is not None and self.ws.open:
-            await self.ws.close()
+            await self.ws.close(code=1000)
 
         self._ready.clear()
 

discord/gateway.py

@@ -543,7 +543,7 @@ class DiscordWebSocket(websockets.client.WebSocketClientProtocol):
         log.debug('Updating our voice state to %s.', payload)
         await self.send_as_json(payload)
 
-    async def close(self, code=1000, reason=''):
+    async def close(self, code=4000, reason=''):
         if self._keep_alive:
             self._keep_alive.stop()
 

discord/shard.py

@@ -290,7 +290,7 @@ class AutoShardedClient(Client):
             except Exception:
                 pass
 
-        to_close = [asyncio.ensure_future(shard.ws.close(), loop=self.loop) for shard in self.shards.values()]
+        to_close = [asyncio.ensure_future(shard.ws.close(code=1000), loop=self.loop) for shard in self.shards.values()]
         if to_close:
             await asyncio.wait(to_close)