Flush all events before polling for read

Once the udev socket becomes readable multiple events might be pulled
of. So all of them should be drained before polling for socket
readability again

Fixes: jeandudey#17

Signed-off-by: Sjoerd Simons <[email protected]>

tokio-udev/src/lib.rs

@@ -89,13 +89,17 @@ impl Inner {
         &mut self,
         ctx: &mut std::task::Context,
     ) -> Poll<Option<Result<udev::Event, io::Error>>> {
-        match self.fd.poll_read_ready(ctx) {
-            Poll::Ready(Ok(mut ready_guard)) => {
-                ready_guard.clear_ready();
-                Poll::Ready(self.fd.get_mut().next().map(Ok))
+        loop {
+            if let Some(e) = self.fd.get_mut().next() {
+                return Poll::Ready(Some(Ok(e)));
+            }
+            match self.fd.poll_read_ready(ctx) {
+                Poll::Ready(Ok(mut ready_guard)) => {
+                    ready_guard.clear_ready();
+                }
+                Poll::Ready(Err(err)) => return Poll::Ready(Some(Err(err))),
+                Poll::Pending => return Poll::Pending,
             }
-            Poll::Ready(Err(err)) => Poll::Ready(Some(Err(err))),
-            Poll::Pending => Poll::Pending,
         }
     }
 }