Fix spawn_count heuristic

src/lib.rs

@@ -261,6 +261,7 @@ impl Inner {
     fn prune(&mut self) {
         self.head_available = None;
         self.prune_time = Instant::now();
+        self.spawn_count = 0;
     }
 
     fn wake(&mut self, task: Arc<Task>) {
@@ -400,6 +401,7 @@ impl Executor {
             thread: std::thread::current(),
         })
         .into();
+
         let mut block_on_context = Context::from_waker(&block_on_waker);
 
         loop {