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

common/net/packet/packet_windows.go

@@ -0,0 +1,15 @@
+//go:build windows
+
+package packet
+
+import (
+	"net"
+)
+
+type enhanceUDPConn struct {
+	*net.UDPConn
+}
+
+func (c *enhanceUDPConn) WaitReadFrom() (data []byte, put func(), addr net.Addr, err error) {
+	return waitReadFrom(c.UDPConn)
+}