tlsSocket.servername
与套接字关联的 SNI（服务器名称指示）主机名。在握手完成之前是 null。握手完成后，它会确定为主机名字符串，或者如果未使用 SNI，则为 false。
🌐 The SNI (Server Name Indication) host name associated with the socket. This is
null before the handshake completes. Once the handshake completes it settles
as either the host name string, or false if SNI was not used.