private void Init(string serverUri)
        {
            var key = Utils.GetApiKey(serverUri, this);

            _keyId     = key.Value <string>("id");
            _serverUri = serverUri;

            this.DefaultRequestHeaders.Add(HeaderNames.Access_Token, "Bearer " + key.Value <string>("access_token"));
            this.DefaultRequestHeaders.Add("Accept", "application/hal+json");
        }