C# HttpClient misused header name fail

C# 使用 HttpClient 的時候出現 Misused header name. 的 Fail

我的用法是醬子

httpClient.DefaultRequestHeaders.Add("Content-Type", "application/json");

沒錯 跟智障一樣
解法可用

httpClient.DefaultRequestHeaders.Add("Accept", "application/json");

或是

httpClient.DefaultRequestHeaders
          .Accept
          .Add(new MediaTypeWithQualityHeaderValue("application/json")); //ACCEPT header

Github: How do you set the Content-Type header for an HttpClient request?

Wikipedia: HTTP Header