import jakarta.servlet.http.HttpServletResponse;

/**
 * SPNEGO (Security Provider Negotiation Protocol) authenticator implementation.
 *
 * This class provides Single Sign-On (SSO) authentication using the SPNEGO protocol,
 * which is commonly used for Kerberos-based authentication in Windows environments.
 * It handles the negotiation between client and server to establish a secure

     * protocols. The http/1.1 transport will never be dropped.
     *
     * If multiple protocols are specified, [ALPN][alpn] will be used to negotiate a transport.
     * Protocol negotiation is only attempted for HTTPS URLs.
     *
     * [Protocol.HTTP_1_0] is not supported in this set. Requests are initiated with `HTTP/1.1`. If