commit dcf5017

Prevent possible deadlock in the typing system

When being flooded by typing notifications, we could steal the lock from
the routine supposed to empty the notification channel.

This caused a possible deadlock in rare cases.

 1@@ -72,9 +72,10 @@ func (ts *Typings) Active(target, name string) {
 2 		time.Sleep(6 * time.Second)
 3 
 4 		ts.l.Lock()
 5-		defer ts.l.Unlock()
 6+		closed := ts.closed
 7+		ts.l.Unlock()
 8 
 9-		if !ts.closed {
10+		if !closed {
11 			ts.timeouts <- t
12 		}
13 	}()