protected override System.Threading.Tasks.Task <HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { string normalizedUri; string authHeader; string normalizedParameters; var url = AuthBase.GenerateSignature( request.RequestUri, ApiKey, ApiSecret, UserToken, UserSecret, request.Method.Method, AuthBase.GenerateTimeStamp(), AuthBase.GenerateNonce(), out normalizedUri, out normalizedParameters, out authHeader); request.Headers.Authorization = new AuthenticationHeaderValue("OAuth", authHeader); return(base.SendAsync(request, cancellationToken)); }