Move connection closure outside of library to the client code in case of UDP Associate

dialer.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"net"
 	"time"
 )
@@ -163,12 +162,6 @@ func (s *Dialer) handleUDP(conn net.Conn, addr *Addr) (*UDPConn, error) {
 		return nil, err
 	}
 
-	go func() {
-		io.Copy(io.Discard, conn)
-		conn.Close()
-		packetConn.Close()
-	}()
-
 	remoteAddr, err := AddrFromSocks(rep.ATYP, rep.BindAddr, rep.BindPort).UDP()
 	if err != nil {
 		return nil, err