add tcp redirect

pkg/handler/redirect/metadata.go

@@ -0,0 +1,18 @@
+package redirect
+
+import (
+	md "github.com/go-gost/gost/pkg/metadata"
+)
+
+type metadata struct {
+	retryCount int
+}
+
+func (h *redirectHandler) parseMetadata(md md.Metadata) (err error) {
+	const (
+		retryCount = "retry"
+	)
+
+	h.md.retryCount = md.GetInt(retryCount)
+	return
+}