chore: decrease direct udp read memory used for no-windows platform

adapter/outbound/base.go

@@ -220,7 +220,7 @@ func NewConn(c net.Conn, a C.ProxyAdapter) C.Conn {
 }
 
 type packetConn struct {
-	net.PacketConn
+	N.EnhancePacketConn
 	chain                   C.Chain
 	adapterName             string
 	connID                  string
@@ -242,15 +242,27 @@ func (c *packetConn) AppendToChains(a C.ProxyAdapter) {
 }
 
 func (c *packetConn) LocalAddr() net.Addr {
-	lAddr := c.PacketConn.LocalAddr()
+	lAddr := c.EnhancePacketConn.LocalAddr()
 	return N.NewCustomAddr(c.adapterName, c.connID, lAddr) // make quic-go's connMultiplexer happy
 }
 
+func (c *packetConn) Upstream() any {
+	return c.EnhancePacketConn
+}
+
+func (c *packetConn) WriterReplaceable() bool {
+	return true
+}
+
+func (c *packetConn) ReaderReplaceable() bool {
+	return true
+}
+
 func newPacketConn(pc net.PacketConn, a C.ProxyAdapter) C.PacketConn {
 	if _, ok := pc.(syscall.Conn); !ok { // exclusion system conn like *net.UDPConn
 		pc = N.NewDeadlinePacketConn(pc) // most conn from outbound can't handle readDeadline correctly
 	}
-	return &packetConn{pc, []string{a.Name()}, a.Name(), utils.NewUUIDV4().String(), parseRemoteDestination(a.Addr())}
+	return &packetConn{N.NewEnhancePacketConn(pc), []string{a.Name()}, a.Name(), utils.NewUUIDV4().String(), parseRemoteDestination(a.Addr())}
 }
 
 func parseRemoteDestination(addr string) string {

adapter/outbound/direct.go

@@ -3,8 +3,6 @@ package outbound
 import (
 	"context"
 	"errors"
-	"net"
-
 	"github.com/Dreamacro/clash/component/dialer"
 	"github.com/Dreamacro/clash/component/resolver"
 	C "github.com/Dreamacro/clash/constant"
@@ -39,11 +37,7 @@ func (d *Direct) ListenPacketContext(ctx context.Context, metadata *C.Metadata,
 	if err != nil {
 		return nil, err
 	}
-	return newPacketConn(&directPacketConn{pc}, d), nil
-}
-
-type directPacketConn struct {
-	net.PacketConn
+	return newPacketConn(pc, d), nil
 }
 
 func NewDirect() *Direct {