fix metadata

dialer/http2/h2/metadata.go

@@ -1,23 +1,33 @@
 package h2
 
 import (
+	"net/http"
+
 	mdata "github.com/go-gost/core/metadata"
 	mdx "github.com/go-gost/x/metadata"
 )
 
 type metadata struct {
-	host string
-	path string
+	host   string
+	path   string
+	header http.Header
 }
 
 func (d *h2Dialer) parseMetadata(md mdata.Metadata) (err error) {
 	const (
-		host = "host"
-		path = "path"
+		host   = "host"
+		path   = "path"
+		header = "header"
 	)
 
 	d.md.host = mdx.GetString(md, host)
 	d.md.path = mdx.GetString(md, path)
-
+	if m := mdx.GetStringMapString(md, header); len(m) > 0 {
+		h := http.Header{}
+		for k, v := range m {
+			h.Add(k, v)
+		}
+		d.md.header = h
+	}
 	return
 }