FSharp.Data 分段上传给出“预期的内容处置：表单数据”错误

Question

我正在尝试使用 FSharp.Data 发出多部分请求：

let stream =
new System.IO.MemoryStream(someByteArray) :> System.IO.Stream

let parts =
    [ FSharp.Data.MultipartItem("file", "file.pdf", stream) ]

let body =
    FSharp.Data.Multipart(boundary = System.Guid.NewGuid().ToString(), parts = parts)

FSharp.Data.Http.AsyncRequest
    (url = "https://some.server.com",
     httpMethod = "POST",
     body = body,
     headers = [ "Authorization", authHeader ])
|> Async.RunSynchronously
|> fun result -> printfn "res: %A" result.Body

响应正文包含此错误： Expected content-disposition: form-data but got Nothing

我用Fiddler查看了请求，它看起来像这样：

POST https://some.server.com HTTP/1.1
Host: some.server.com
Authorization: MY-AUTH-CREDENTIALS
Connection: Keep-Alive
Accept-Encoding: gzip, deflate
Content-Type: multipart/form-data; boundary=81b62ec3-3fee-44b6-8651-2f39f0a72de0
Content-Length: 469

--81b62ec3-3fee-44b6-8651-2f39f0a72de0
Content-Disposition: form-data; name="file"; filename="file.pdf"
Content-Type: application/pdf

PDF-CONTENT-HERE
--81b62ec3-3fee-44b6-8651-2f39f0a72de0--

当我使用 Postman 和Http.fs提出完全相同的请求时，它可以工作。

有任何想法吗？