feat: VLESS support packet encodings (#334)

* adjust: Do not use XTLS on H2 connections

* feat: VLESS support XUDP fullcone NAT

* fix: VLESS with PacketAddr does not work

* fix: VLESS XUDP crash

transport/vless/vless.go

@@ -1,9 +1,10 @@
 package vless
 
 import (
-	"github.com/Dreamacro/clash/common/utils"
 	"net"
 
+	"github.com/Dreamacro/clash/common/utils"
+
 	"github.com/gofrs/uuid"
 )
 
@@ -19,6 +20,7 @@ const (
 const (
 	CommandTCP byte = 1
 	CommandUDP byte = 2
+	CommandMux byte = 3
 )
 
 // Addr types
@@ -33,7 +35,8 @@ type DstAddr struct {
 	UDP      bool
 	AddrType byte
 	Addr     []byte
-	Port     uint
+	Port     uint16
+	Mux      bool // currently used for XUDP only
 }
 
 // Client is vless connection generator