更新到4.3.1.0后kcptun无法正常使用，但是在4.2.1.0使用正常

环境

windows10 x64 20H2

• Shadowsocks客户端版本：4.3.1.0
• 操作系统版本：windows 19042.610
• .NET版本：4.8

###操作步骤
在4.3.1.0中使用kcptun插件无法正常 工作，直接替换shadowsocks.exe文件，可以反复复现kcptun的失败和成功，结果是4.3.1.0总是失败，而在4.2.1.0一直成功。
确认kcptun的配置没有问题，因为没有改动过，而服务端的kcptun也确定没有问题，在其他平台的客户端（mac、ios）上都正常使用。
4.3.1.0日志如下：
2020-11-02 22:29:03.2899|INFO|Shadowsocks.Controller.I18N|Current language is: zh-CN
2020-11-02 22:29:03.3759|INFO|Shadowsocks.Controller.UpdateChecker|Waiting for 3000ms before checking for version update.
2020-11-02 22:29:03.4649|INFO|Shadowsocks.Controller.ShadowsocksController|WPF Localization Extension|Current culture: zh-CN
2020-11-02 22:29:03.7989|INFO|Shadowsocks.Controller.Listener|Shadowsocks started (4.3.1.0)
2020-11-02 22:29:06.3799|INFO|Shadowsocks.Controller.UpdateChecker|Checking for version update.
2020-11-02 22:29:08.3372|INFO|Shadowsocks.Controller.UpdateChecker|No new versions found.
2020-11-02 22:29:14.0888|INFO|Shadowsocks.Controller.ShadowsocksController|WPF Localization Extension|Current culture: zh-CN
2020-11-02 22:29:14.2957|INFO|Shadowsocks.Controller.Listener|Shadowsocks started (4.3.1.0)
2020-11-02 22:30:33.9524|INFO|Shadowsocks.Controller.ShadowsocksController|WPF Localization Extension|Current culture: zh-CN
2020-11-02 22:30:34.7337|INFO|Shadowsocks.Controller.ShadowsocksController|Started SIP003 plugin for 173.82.106.129:10510 on 127.0.0.1:1935 - PID: 16284
2020-11-02 22:30:35.0177|INFO|Shadowsocks.Controller.Listener|Shadowsocks started (4.3.1.0)

插件日志如下：

2020/11/02 22:36:05 stream closed
2020/11/02 22:36:05 stream closed
2020/11/02 22:36:05 stream closed
2020/11/02 22:36:05 stream closed
2020/11/02 22:36:05 stream closed
2020/11/02 22:36:05 session marked as expired
2020/11/02 22:36:05 connection: 10.201.102.178:49404 -> 173.82.106.129:10510
2020/11/02 22:36:05 stream opened
2020/11/02 22:36:05 stream opened
2020/11/02 22:36:05 stream opened
2020/11/02 22:36:05 stream opened
2020/11/02 22:36:05 stream opened
2020/11/02 22:36:05 stream closed
2020/11/02 22:36:05 stream closed
2020/11/02 22:36:06 session normally closed
2020/11/02 22:36:10 stream opened