How to tell Web API 2.1 to allow errors to propagate up the MessageHandler pipeline so all exceptions can be converted to HttpResponseMessages in one place.

gistfile1.cs

    class Program
    {
        static void Main(string[] args)
        {

            var server = WebApp.Start("http://localhost:1002/", (app) =>
            {
                var config = new HttpConfiguration();
                config.MapHttpAttributeRoutes();
                config.Services.Replace(typeof(IExceptionHandler), new RethrowExceptionHandler());
                config.MessageHandlers.Add(new ErrorTrapHandler());
                app.UseWebApi(config);
            });


            Console.ReadLine();
            server.Dispose();

        }
    }
    public class RethrowExceptionHandler : IExceptionHandler {
        public Task HandleAsync(ExceptionHandlerContext context, CancellationToken cancellationToken)
        {
            return Task.FromResult(0);
        }
}

    public class ErrorTrapHandler : DelegatingHandler
    {
        protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            try
            {
                return await base.SendAsync(request, cancellationToken);
            }
            catch (Exception ex)
            {
                return new HttpResponseMessage
                {
                    ReasonPhrase = ex.Message,
                    StatusCode = HttpStatusCode.InternalServerError
                };
            }
        }
    }