public async Task Execute(CancellationToken cancellationToken, IProgress <double> progress)
        {
            var    gravatarManager = new GravatarManager(_providerManager, _logger);
            var    users           = _userManager.Users.ToList();
            var    percentPerUser  = 100 / users.Count;
            var    numComplete     = 0;
            double currentProgress = 0;

            foreach (var user in users)
            {
                await gravatarManager.Post(user, CancellationToken.None).ConfigureAwait(false);

                numComplete++;
                currentProgress = percentPerUser * numComplete;
                progress.Report(currentProgress);
            }
        }