fix transparent proxy

handler/redirect/tcp/metadata.go

@@ -0,0 +1,17 @@
+package redirect
+
+import (
+	mdata "github.com/go-gost/core/metadata"
+)
+
+type metadata struct {
+	sniffing bool
+}
+
+func (h *redirectHandler) parseMetadata(md mdata.Metadata) (err error) {
+	const (
+		sniffing = "sniffing"
+	)
+	h.md.sniffing = mdata.GetBool(md, sniffing)
+	return
+}