使用Golang调用QuickBooks Online API上传多附件时出现Content-Disposition头缺失错误

我使用Golang构建POST请求调用QuickBooks Online API的上传端点：https://quickbooks.api.intuit.com/v3/company/XXXXXX/upload?minorversion=65，收到的JSON错误响应如下：

{"Fault":{"Error":[{"Message":"An application error has occurred while processing your request","Detail":"System Failure Error: Could find no Content-Disposition header within part","code":"10000"}],"type":"SystemFault"},"time":"2023-09-20T14:19:11.865-07:00"}

我构造的多部分表单数据如下：

--af033f6ccf0906f358c1d8d104c2778d6e2b95f61d13903a25f8f56cc28b
Content-Disposition: form-data; name="file_metadata_1"; filename="RT00404582_10-10-23.pdf"
Content-Type: application/json

{"AttachableRef":[{"EntityRef":{"type":"Bill","value":"153061"}}],"ContentType":"application/pdf","FileName":"RT00404582_10-10-23.pdf"}
--af033f6ccf0906f358c1d8d104c2778d6e2b95f61d13903a25f8f56cc28b
Content-Disposition: form-data; name="file_content_1"; filename="RT00404582_10-10-23.pdf"
Content-Type: application/pdf

<BINARY FILE DATA>

--af033f6ccf0906f358c1d8d104c2778d6e2b95f61d13903a25f8f56cc28b--

我仅找到一个格式与之匹配的示例，但API文档中没有相关示例及格式说明，请问为何会出现无法读取请求头的问题？

内容的提问来源于stack exchange，提问作者vinniyo