diff --git a/go.mod b/go.mod
index b715aa4b5..566ecd8b2 100644
--- a/go.mod
+++ b/go.mod
@@ -26,6 +26,7 @@ require (
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
 	github.com/leodido/go-urn v1.1.0 // indirect
 	github.com/mattn/go-colorable v0.1.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/montanaflynn/stats v0.5.0
 	github.com/openzipkin/zipkin-go v0.2.1
 	github.com/otokaze/mock v0.0.0-20190125081256-8282b7a7c7c3