https://learn.microsoft.com/ja-jp/uwp/api/windows.web.http.headers.httplanguageheadervaluecollection?view=winrt-28000
HttpLanguageHeaderValueCollection Class (Windows.Web.Http.Headers) - Windows apps | Microsoft Learn
Represents the value of the Content-Language HTTP header on HTTP content in a request or a response.
http headersclasswindowswebapps