Add support for setting application_id

discord/client.py

@@ -113,6 +113,8 @@ class Client:
         Integer starting at ``0`` and less than :attr:`.shard_count`.
     shard_count: Optional[:class:`int`]
         The total number of shards.
+    application_id: :class:`int`
+        The client's application ID.
     intents: :class:`Intents`
         The intents that you want to enable for the session. This is a way of
         disabling and enabling certain gateway events from triggering and being sent.
@@ -306,6 +308,16 @@ class Client:
         """
         return self._connection.voice_clients
 
+    @property
+    def application_id(self):
+        """Optional[:class:`int`]: The client's application ID.
+
+        If this is not passed via ``__init__`` then this is retrieved
+        through the gateway when an event contains the data. Usually
+        after :func:`on_connect` is called.
+        """
+        return self._connection.application_id
+
     def is_ready(self):
         """:class:`bool`: Specifies if the client's internal cache is ready for use."""
         return self._ready.is_set()