try grpc lb interface

rpcx/lb/main.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"zero/core/discov"
+	"zero/core/lang"
+	"zero/rpcx/internal"
+)
+
+func main() {
+	cli, err := internal.NewDiscovClient(discov.EtcdConf{
+		Hosts: []string{"localhost:2379"},
+		Key:   "rpcx",
+	})
+	lang.Must(err)
+
+	cli.Next()
+}