服务器兼容性问题: MailKit 4.16.0 连接 imap.sohu.com:993 时出现 CAPABILITIES 异常

**主机**：imap.sohu.com **端口**：993 **日志**：已连接到 imaps://imap.sohu.com:993/ S: * OK IMAP4 ready C: C00000000 CAPABILITY S: * CAPABILITY IMAP4 IMAP4rev1 UIDPLUS IDLE AUTH=PLAIN S: C00000000 OK completed C: C00000001 AUTHENTICATE PLAIN S: + C: ******* S: C00000001 OK LOGIN completed C: C00000002 CAPABILITY S: * CAPABILITY IMAP4 IMAP4rev1 AUTH=LOGIN IDLE MOVE NAMESPACE S: C00000002 OK CAPABILITY completed C: C00000003 NAMESPACE S: * CAPABILITY (("" "/")) NIL NIL