feat: Serve never returns

src/tftp/server.rs

@@ -145,7 +145,7 @@ where
     Ok(())
 }
 
-pub async fn serve<F, Fut>(callback: F) -> Result<(), Error>
+pub async fn serve<F, Fut>(callback: F) -> Result<!, Error>
 where
     F: Fn(&str) -> Fut + Clone + Send + 'static,
     Fut: Future<Output = Option<Vec<u8>>> + Send + 'static,