/**
 * All custom headers used by auth-vir.
 *
 * @category Internal
 */
export declare enum AuthHeaderName {
    AssumedUser = "assumed-user",
    /**
     * Used to track if the current user is signed in only with a sign-up cookie, which prevents us
     * from prematurely wiping their CSRF token.
     */
    IsSignUpAuth = "is-sign-up-auth"
}
/**
 * Merges multiple header values into a single array of header values.
 *
 * @category Internal
 */
export declare function mergeHeaderValues(...values: (string | string[] | undefined)[]): string[];