drop writer before joining worker thread

tracing-appender/src/worker.rs

@@ -73,6 +73,7 @@ impl<T: Write + Send + Sync + 'static> Worker<T> {
                 match self.work() {
                     Ok(WorkerState::Continue) | Ok(WorkerState::Empty) => {}
                     Ok(WorkerState::Shutdown) | Ok(WorkerState::Disconnected) => {
+                        drop(self.writer); // drop now in case it blocks
                         let _ = self.shutdown.recv();
                         return;
                     }