diff --git a/monoio/src/builder.rs b/monoio/src/builder.rs
index e7fb8728..860c4880 100644
--- a/monoio/src/builder.rs
+++ b/monoio/src/builder.rs
@@ -40,6 +40,8 @@ impl<T> Default for RuntimeBuilder<T> {
     /// [monoio::blocking::BlockingStrategy] is to execute tasks on the local thread. In other
     /// words, there is no thread pool involved—all blocking I/O operations and heavy computations
     /// will block the current thread.
+    #[allow(unused_attributes)]
+    #[must_use]
     fn default() -> Self {
         RuntimeBuilder::<T>::new()
     }