rm unnecessary boxing (#33)

Author: 6293

src/lib.rs

@@ -18,16 +18,17 @@ pub fn diff(lhs: Value, rhs: Value) -> Result<Vec<Change>, Error> {
     let rhs_root: RootSchema = serde_json::from_value(rhs)?;
 
     let mut changes = vec![];
-    let cb = |change: Change| {
-        changes.push(change);
-    };
-    let mut walker = diff_walker::DiffWalker::new(Box::new(cb), lhs_root, rhs_root);
+    let mut walker = diff_walker::DiffWalker::new(
+        |change: Change| {
+            changes.push(change);
+        },
+        lhs_root,
+        rhs_root,
+    );
     walker.diff(
         "",
         &mut walker.lhs_root.schema.clone(),
         &mut walker.rhs_root.schema.clone(),
     )?;
-    drop(walker);
-
     Ok(changes)
 }