private void RequestTokenAndSignIn(IDictionary <string, object> parameters)
{
parameters.Add("client_id", _apiConfig.ClientId);
parameters.Add("client_secret", _apiConfig.ClientSecret);
var client = new RestClient(_apiConfig.BaseUrl + "oauth/token");
var request = new RestRequest(Method.POST);
request.AddHeader("cache-control", "no-cache");
request.AddHeader("content-type", "application/x-www-form-urlencoded");
request.AddParameter("application/x-www-form-urlencoded", AuthHelpers.CreateQueryString(parameters), ParameterType.RequestBody);
var response = client.Execute(request);
var oAuthToken = JsonSerializer.Deserialize <OAuthTokenResponse>(response.Content);
SignIn(oAuthToken.access_token);
}