FlickrNet.TwitterResponder.GetDataResponseOAuthAsync C# (CSharp) Method

        private async static Task<FlickrResult<string>> GetDataResponseOAuthAsync(Twitter flickr, string method, string baseUrl, Dictionary<string, string> parameters)
        {
            if (parameters.ContainsKey("api_key")) parameters.Remove("api_key");

            if (parameters.ContainsKey("api_sig")) parameters.Remove("api_sig");

            if (!String.IsNullOrEmpty(flickr.OAuthAccessToken) && !parameters.ContainsKey("oauth_token"))
            {
                parameters.Add("oauth_token", flickr.OAuthAccessToken);
            }
            if (!String.IsNullOrEmpty(flickr.OAuthAccessTokenSecret) && !parameters.ContainsKey("oauth_signature"))
            {
                string sig = flickr.OAuthCalculateSignatureForCalls(method, baseUrl, parameters, flickr.OAuthAccessTokenSecret);
                parameters.Add("oauth_signature", sig);
            }

            string data = OAuthCalculatePostData(parameters);

            string authHeader = OAuthCalculateAuthHeader(parameters);


            baseUrl = baseUrl.Split("?".ToCharArray())[0];

            if (method == "GET") return await DownloadDataAsync(method, baseUrl, data, GetContentType, authHeader);
            else return await DownloadDataAsync(method, baseUrl, data, PostContentType, authHeader);

        }