/// <summary>
        /// Returns an Allow HTTP header with the allowed HTTP methods.
        /// </summary>
        /// <returns>A 200 OK response.</returns>
        [HttpOptions]
        [SwaggerResponse(StatusCodes.Status200OK, "The allowed HTTP methods.")]
        public IActionResult Options()
        {
            this.HttpContext.Response.Headers.AppendCommaSeparatedValues(
                HeaderNames.Allow,
                HttpMethods.Get,
                HttpMethods.Head,
                HttpMethods.Options,
                HttpMethods.Post);
            return this.Ok();
        }

        /// <summary>
        /// Returns an Allow HTTP header with the allowed HTTP methods for a car with the specified unique identifier.
        /// </summary>
        /// <param name="carId">The cars unique identifier.</param>
        /// <returns>A 200 OK response.</returns>
        [HttpOptions("{carId}")]
        [SwaggerResponse(StatusCodes.Status200OK, "The allowed HTTP methods.")]
        public IActionResult Options(int carId)
        {
            this.HttpContext.Response.Headers.AppendCommaSeparatedValues(
                HeaderNames.Allow,
                HttpMethods.Delete,
                HttpMethods.Get,
                HttpMethods.Head,
                HttpMethods.Options,
                HttpMethods.Patch,
                HttpMethods.Post,
                HttpMethods.Put);
            return this.Ok();
        }