updated steam.client.gc docs to clarify usage

steam/client/gc.py

@@ -1,12 +1,21 @@
 """
-Example usage for messages to the Dota 2 GC.
+:class:`GameCoordinator` is used to proxy messages from/to GC.
+It takes care of the encapsulation details, but on it's own is not
+enough to communicate with a given GC.
+
+Example usage for sending client hello to Dota 2's GC.
 
 .. code:: python
 
+    import myDotaModule
     from steam import SteamClient
+    from steam.core.msg import GCMsgHdrProto
     from steam.client.gc import GameCoordinator
 
     client = SteamClient()
+
+    # login logic etc
+
     gc = GameCoordinator(client, 570)
 
     @gc.on(None)
@@ -15,8 +24,19 @@ Example usage for messages to the Dota 2 GC.
 
     @gc.on(4004)  # EMsgGCClientWelcome
     def handle_client_welcome(header, body):
-        passs
+        message = myDotaModule.gcsdk_gcmessages_pb2.CMsgClientWelcome()
+        message.ParseFromString(body)
+
+    # indicate to steam that we are playing Dota 2
+    client.games_played([570])
 
+    # send client hello
+    header = GCMsgHdrProto(4006)  # EMsgGCClientHello
+    body = myDotaModule.gcsdk_gcmessages_pb2.CMsgClientHello()
+    gc.send(header, body.SerializeToString())
+
+The above code assumes that we have a ``myDotaModule`` that contains the appropriate
+data structures, which can be used to (de)serialize messages. For example, protobufs.
 """
 import logging
 import gevent
@@ -29,12 +49,19 @@ from steam.core.msg import GCMsgHdr, GCMsgHdrProto, MsgProto
 
 class GameCoordinator(EventEmitter):
     """
-    GameCoordinator is used to proxy messages from/to GC
+    ``GameCoordinator`` is used to proxy messages from/to GC
 
     :param steam_client: steam client instance
     :type steam_client: :class:`steam.client.SteamClient`
     :param app_id: app id of the application
     :type app_id: :class:`int`
+
+    Incoming messages are emitted as events using their ``EMsg`` as an event identifier.
+
+    :param header: message header
+    :type header: :class:`steam.core.msg.GCMsgHdr`
+    :param body: raw message body
+    :type body: :class:`bytes`
     """
 
     def __init__(self, steam_client, app_id):