Add xhttp transport

common/xray/task/common.go

@@ -0,0 +1,10 @@
+package task
+
+import "github.com/sagernet/sing-box/common/xray"
+
+// Close returns a func() that closes v.
+func Close(v interface{}) func() error {
+	return func() error {
+		return common.Close(v)
+	}
+}