c# – 带有ExecuteReaderAsync的ASP.NET webapi HttpResponseMes

我不想在Web服务器上缓冲内存中的blob数据.

我有以下代码,但它不起作用 – 没有例外.

public class AttachmentController : ApiController
{
    public async Task<HttpResponseMessage> Get(int id)
    {
        using (var connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
        {
            await connection.OpenAsync();

            using (var command = new SqlCommand("SELECT Content FROM [Attachments] WHERE ID = @ID",connection))
            {

                command.Parameters.AddWithValue("ID",id);

                using (SqlDataReader reader = await command.ExecuteReaderAsync(CommandBehavior.SequentialAccess))
                {

                    if (await reader.ReadAsync())
                    {
                        using (Stream data = reader.GetStream(0))
                        {
                            var response = new HttpResponseMessage{Content = new StreamContent(data)};
                            //I get this from the DB else where
                            //response.Content.Headers.ContentType = new MediaTypeHeaderValue(attachment.ContentType);
                            //I get this from the DB else where
                            //response.Content.Headers.ContentLength = attachment.ContentLength;
                            return response;

                        }
                    }
                }
            }

            throw new HttpResponseException(HttpStatusCode.NotFound);
        }
    }
}

Fiddle将以下错误写为reposnse：
[Fiddler] ReadResponse()失败：服务器未返回此请求的响应.

如何将内容从数据库流式传输到http输出流,而不在内存中缓冲它？