ensure waiting tasks are cancelled on worker unsubscription

Author: davidmoten

src/main/java/rx/schedulers/ExecutorScheduler.java

@@ -96,18 +96,17 @@ public Subscription schedule(Action0 action) {
         @Override
         public void run() {
             do {
-                if (tasks.isUnsubscribed()) {
-                    queue.clear();
-                    return;
-                }
-
                 ScheduledAction sa = queue.poll();
                 if (sa == null) {
                     return;
                 }
-
                 if (!sa.isUnsubscribed()) {
-                    sa.run();
+                    if (!tasks.isUnsubscribed()) {
+                        sa.run();
+                    } else {
+                        queue.clear();
+                        return;
+                    }
                 }
             } while (wip.decrementAndGet() != 0);
         }