在Http请求中设置头

我们正在从应用程序调用Odata终结点。odata端点不需要像下面这样的头

               ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(delegate { return true; });
                Uri uri = new Uri(BaseURL_Core);
                client_Core.BaseAddress = uri;
                client_Core.DefaultRequestHeaders.Accept.Clear();
                client_Core.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                client_Core.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray_Core));

如何在这里设置 Prefer