Add overridable method self.configure_socket().

Allows for setting app specific socket timeouts and other socket options.

sleekxmpp/xmlstream/xmlstream.py

@@ -342,7 +342,7 @@ class XMLStream(object):
             self.address = self.pick_dns_answer(self.default_domain,
                                                 self.address[1])
         self.socket = self.socket_class(Socket.AF_INET, Socket.SOCK_STREAM)
-        self.socket.settimeout(None)
+        self.configure_socket()
 
         if self.reconnect_delay is None:
             delay = 1.0
@@ -532,6 +532,14 @@ class XMLStream(object):
             if not ignore:
                 self.state._set_state('connected')
 
+    def configure_socket(self):
+        """
+        Set timeout and other options for self.socket.
+
+        Meant to be overridden.
+        """
+        self.socket.settimeout(None)
+
     def start_tls(self):
         """
         Perform handshakes for TLS.