HTTP请求标头 HttpWorkerRequest.HeaderContentType

// 获取 HttpWorkerRequest引用
        

        IServiceProvider provider = (IServiceProvider)HttpContext.Current;
        HttpWorkerRequest request = (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
        string contentType = request.GetKnownRequestHeader(HttpWorkerRequest.HeaderContentType);

multipart/form-data; boundary=---------------------------7d821335201de