diff --git a/actix-rt/src/builder.rs b/actix-rt/src/builder.rs
index 76ff75d5..2dbc9766 100644
--- a/actix-rt/src/builder.rs
+++ b/actix-rt/src/builder.rs
@@ -108,7 +108,7 @@ impl Builder {
 }
 
 #[derive(Debug)]
-pub(crate) struct AsyncSystemRunner {
+pub struct AsyncSystemRunner {
     stop: Receiver<i32>,
     system: System,
 }