Add loopback outound

infra/conf/loopback.go

@@ -0,0 +1,15 @@
+package conf
+
+import (
+	"github.com/golang/protobuf/proto"
+
+	"github.com/xtls/xray-core/proxy/loopback"
+)
+
+type LoopbackConfig struct {
+	InboundTag string `json:"inboundTag"`
+}
+
+func (l LoopbackConfig) Build() (proto.Message, error) {
+	return &loopback.Config{InboundTag: l.InboundTag}, nil
+}