Fix experimental_handle_disconnect_ack 'feature' conditional compilation

* Renamed from experimental-handle_disconnect_ack to experimental_handle_disconnect_ack
* Fixed conditional compilation by removing space at the end of the cfg macro

Author: Martijn

Cargo.toml

@@ -14,7 +14,7 @@ msrv = "1.38"
 exclude = ["/.github", "docs/sketches/*.png"]
 
 [features]
-experimental-handle_disconnect_ack = []
+experimental_handle_disconnect_ack = []
 
 [dependencies]
 crossbeam-channel = "0.5"

src/listener.rs

@@ -181,13 +181,12 @@ where
                     Err(_disconnect) => {
                         handler.finish();
 
-                        let ack = disconnect_sender.acknowledge_disconnection();
+                        let _ack = disconnect_sender.acknowledge_disconnection();
 
-                        #[cfg(feature = "experimental-handle_disconnect_ack ")]
-                        ack.unwrap_or_default();
-
-                        #[cfg(not(feature = "experimental-handle_disconnect_ack "))]
-                        ack.expect("Failed to send disconnect acknowledgement!");
+                        #[cfg(not(feature = "experimental_handle_disconnect_ack"))]
+                        {
+                            _ack.expect("Failed to send disconnect acknowledgement!");
+                        }
 
                         break;
                     }