public FacebookApiService(IGraphApiConfiguration configuration)
        {
            this.configuration = configuration;
            this.apiUrl        = !string.IsNullOrEmpty(this.configuration.ApiUrl) ? this.configuration.ApiUrl : FacebookApiConstants.ApiUrl;

            // wrap the end slash char in case user forgot about it
            if (!this.apiUrl.EndsWith("/"))
            {
                this.apiUrl = $"{this.apiUrl}/";
            }
        }
        internal static bool Validate(IGraphApiConfiguration config, DebugTokenResponse model)
        {
            DateTimeOffset expiredAtOffset = DateTimeOffset.FromUnixTimeSeconds(model.ExpiresAt);
            DateTime       expiredAtUtc    = expiredAtOffset.UtcDateTime;

            if (model.IsTokenValid && model.AppId == config.ApplicationId && DateTime.UtcNow < expiredAtUtc)
            {
                return(true);
            }

            return(false);
        }