[FIX]:'all' should be followed by the plural form of the noun. (#2286)
diff --git a/protocol/protocol.go b/protocol/protocol.go
index ff5356e..9460577 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -35,7 +35,7 @@
//
// # Refer method is to refer a remote service
//
-// Destroy method will destroy all invoker and exporter, so it only is called once.
+// Destroy method will destroy all invokers and exporters, so it only is called once.
type Protocol interface {
Export(invoker Invoker) Exporter
Refer(url *common.URL) Invoker
