diff --git a/runtime/internal/flow/conn/grpc/conn.go b/runtime/internal/flow/conn/grpc/conn.go
index d319973..646dab3 100644
--- a/runtime/internal/flow/conn/grpc/conn.go
+++ b/runtime/internal/flow/conn/grpc/conn.go
@@ -13,7 +13,7 @@
 	_ "io/ioutil"
 	"log"
 	"net"
-	"runtime/debug"
+	_ "runtime/debug"
 	"sync"
 	"time"