ToResourceResponse.cs

public static ResourceResponse<T> ToResourceResponse<T>(this T resource, HttpStatusCode statusCode, IDictionary<string, string> responseHeaders = null) where T : Resource, new()
{
    var resourceResponse = new ResourceResponse<T>(resource);
    var documentServiceResponseType = Type.GetType("Microsoft.Azure.Documents.DocumentServiceResponse, Microsoft.Azure.DocumentDB.Core, Version=1.9.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35");

    var flags = BindingFlags.NonPublic | BindingFlags.Instance;
    var headers = new NameValueCollection { { "x-ms-request-charge", "0" } };
    if (responseHeaders != null)
    {
        foreach (var responseHeader in responseHeaders)
        {
            headers[responseHeader.Key] = responseHeader.Value;
        }
    }

    var arguments = new object[] { Stream.Null, headers, statusCode, null };
    var documentServiceResponse = Activator.CreateInstance(documentServiceResponseType ?? throw new InvalidOperationException(), flags, null, arguments, null);
    var responseField = typeof(ResourceResponse<T>).GetField("response", BindingFlags.NonPublic | BindingFlags.Instance);
    if (responseField != null) responseField.SetValue(resourceResponse, documentServiceResponse);

    return resourceResponse;
}