diff --git a/vnt/src/util/counter/adder.rs b/vnt/src/util/counter/adder.rs
index 41b840f..38a1749 100644
--- a/vnt/src/util/counter/adder.rs
+++ b/vnt/src/util/counter/adder.rs
@@ -49,7 +49,7 @@ impl SingleU64AdderInner {
         unsafe { *self.ptr }
     }
 }
-impl Drop for SingleU64AdderInner{
+impl Drop for SingleU64AdderInner {
     fn drop(&mut self) {
         unsafe {
             let _ = Box::from_raw(self.ptr);