snowflake-client needs to stop using my network when I'm not giving it requests
I started my Tor Browser, and told it to use snowflake, and it did. Then I changed my mind and told it to stop using snowflake. Now, apparently there's a bug in Tor where Tor is supposed to kill snowflake-client when there are no more bridge lines in my torrc that want to use it. But ignoring that Tor bug, snowflake-client should also be defensive for me. Right now it is touching the broker every 10 seconds, looking for a snowflake, even though it is getting no requests. That can't be good for scalability or for the broker or for the users.