/// <summary>
        /// Get Access Token using refresh token
        /// </summary>
        /// <param name="apiURL">API Uri</param>
        /// <param name="refresh_token">Refresh Token, which can be used to get a fresh Access Token</param>
        /// <param name="clientid">Application ID - obtained from OAuth Configuration page / Identifies the application</param>
        /// <param name="client_secret">Client secret key - obtained from OAuth Configuration page / Authenticates the application</param>
        /// <returns>AccessToken object - Refresh_token property would be null on this call.</returns>
        public static async Task <AccessToken> GetAccessTokenByRefreshToken(string apiURL, string refresh_token, string clientid, string client_secret)
        {
            AdobeRestAPI API = new AdobeRestAPI(apiURL, "");

            Dictionary <string, string> parameters = new Dictionary <string, string>();

            parameters.Add("refresh_token", refresh_token);
            parameters.Add("client_id", clientid);
            parameters.Add("client_secret", client_secret);
            parameters.Add("grant_type", "refresh_token");

            FormUrlEncodedContent encodedContent = new FormUrlEncodedContent(parameters);

            string json = await API.PostRest("/oauth/refresh", encodedContent, "application/x-www-form-urlencoded");

            return(API.DeserializeJSon <AccessToken>(json));
        }
 public AdobeObject()
 {
     API = new AdobeRestAPI();
 }