/** HTTP header names used by Squid for request metadata. */
export declare const SquidHeaders: {
    /** Correlates logs and spans across distributed calls. */
    readonly TRACE_ID: "x-squid-traceid";
    /** Shared secret header for internal authentication. */
    readonly SECRET: "x-squid-secret";
    /** API key provided by the calling application. */
    readonly APP_API_KEY: "x-app-api-key";
    /** Unique identifier of the client application. */
    readonly APP_ID: "x-squid-appid";
    /** Unique identifier of the end user or service client. */
    readonly CLIENT_ID: "x-squid-clientid";
    /** Version string of the Squid client library. */
    readonly CLIENT_VERSION: "x-squid-client-version";
    /** Originating IP address of the request. */
    readonly SOURCE_IP: "x-squid-source-ip";
};