No performance change switching affiliated_key to using element macro.

src/parser/macros.rs

@@ -35,6 +35,11 @@ macro_rules! element {
             return Ok((remaining, ele));
         }
     };
+    ($parser:expr, $input: expr) => {
+        if let Ok((remaining, ele)) = $parser($input) {
+            return Ok((remaining, ele));
+        }
+    };
 }
 
 pub(crate) use element;