Add XXX comment.

Should the deadline by checked inside this final loop waiting for
wrappers to finish?

src/ZEO/zrpc/client.py

@@ -403,6 +403,8 @@ class ConnectThread(threading.Thread):
             assert wrap.state == "closed"
             del wrappers[wrap]
 
+            # XXX should check deadline
+        
 
 class ConnectWrapper:
     """An object that handles the connection procedure for one socket.