如何在ASP.NET WebAPI中返回文件（FileContentResult）

我可以使它与一起使用，而不是返回

StreamContent

Content``ByteArrayContent

[HttpGet]public HttpResponseMessage Generate(){    var stream = new MemoryStream();    // processing the stream.    var result = new HttpResponseMessage(HttpStatusCode.OK)    {        Content = new ByteArrayContent(stream.ToArray())    };    result.Content.Headers.ContentDisposition =        new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")    {        FileName = "CertificationCard.pdf"    };    result.Content.Headers.ContentType =        new MediaTypeHeaderValue("application/octet-stream");    return result;}