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

_2025-10-07_

 *  New: Support [HTTP 101] responses with `Response.socket`. This mechanism is only supported on
    HTTP/1.1. We also reimplemented our websocket client to use this new mechanism.

 *  New: The `okhttp-zstd` module negotiates [Zstandard (zstd)][zstd] compression with servers that
    support it. It integrates a new (unstable) [ZSTD-KMP] library, also from Square. Enable it like
    this:

    ```kotlin
    val client = OkHttpClient.Builder()

- Improved how the API server responds to **list** requests where the response format negotiates to Protobuf. List responses in Protobuf are marshalled one element at the time, drastically reducing memory needed to serve large collections. Streaming list responses can be disabled via the `StreamingCollectionEncodingToProtobuf` feature gate....