test+refactor: identifying missing pieces

engine/jack.rs

@@ -145,7 +145,17 @@ pub trait Audio {
             #[inline] fn process (&mut $self1, $c: &Client, $s: &ProcessScope) -> Control { $cb }
             $(#[inline] fn handle (&mut $self2, $e: JackEvent) { $cb2 })?
         }
-    }
+    };
+    ($Struct:ident: $process:ident, $handle:ident) => {
+        impl Audio for $Struct {
+            #[inline] fn process (&mut self, c: &Client, s: &ProcessScope) -> Control {
+                $process(self, c, s)
+            }
+            #[inline] fn handle (&mut self, e: JackEvent) {
+                $handle(self, e)
+            }
+        }
+    };
 }
 /// Event enum for JACK events.
 #[derive(Debug, Clone, PartialEq)] pub enum JackEvent {