public async Task RemoveTargetAsync(IBackupSyncTarget target) { Guard.IsNotNull(target, nameof(target)); _targets.Remove(target); var a = _targets.Items; if (!a.Any()) { await _cache.RemoveAsync("settings_backupSync_targets"); } else { await _cache.InsertAsync("settings_backupSync_targets", a, _serializer).ConfigureAwait(false); } }