Basic plumbing

AkavacheSamplePage.xaml.cs

private readonly ObservableRangeCollection<Breach> _breaches = new ObservableRangeCollection<Breach>();
public ObservableCollection<Breach> Breaches => _breaches;

private ICommand refreshCommand;
    public ICommand RefreshCommand
    {
        get
        {
            return refreshCommand ??
                (refreshCommand = new Command(() => LoadBreaches(), () => !IsLoading));
        }
    }

private IBeenPwnedClient _pwnedClient = new BeenPwnedClient($"AkavacheSample");