Add support for guild subscriptions.

discord/client.py

@@ -152,6 +152,30 @@ class Client:
         WebSocket in the case of not receiving a HEARTBEAT_ACK. Useful if
         processing the initial packets take too long to the point of disconnecting
         you. The default timeout is 60 seconds.
+    guild_subscriptions: :class:`bool`
+        Whether to dispatching of presence or typing events. Defaults to ``True``.
+
+        .. warning::
+
+            If this is set to ``False`` then the following features will be disabled:
+
+                    - No user related updates (:func:`on_user_update` will not dispatch)
+                    - No presence related changes will be recorded (e.g. :attr:`Member.activities` or :attr:`Member.status`)
+                    - If ``fetch_offline_members`` is set to ``False`` then the user cache will not exist.
+                      This makes it difficult or impossible to do many things, for example:
+
+                        - Computing permissions
+                        - Querying members in a voice channel via :attr:`VoiceChannel.members` will be empty.
+                        - Most forms of receiving :class:`Member` will be
+                          receiving :class:`User` instead, except for message events.
+                        - :attr:`Guild.owner` will usually resolve to ``None``.
+                        - :meth:`Guild.get_member` will usually be unavailable.
+                        - Anything that involves using :class:`Member`.
+                        - :attr:`users` will not be as populated.
+                        - etc.
+
+            In short, this makes it so the only member you can reliably query is the
+            message author. Useful for bots that do not require any state.
 
     Attributes
     -----------