C#: How do you implement async/await?

1public async Task<string> GetDataAsync()
2{
3    using var client = new HttpClient();
4    return await client.GetStringAsync("https://api.example.com");
5}

1var task1 = GetDataAsync();
2var task2 = GetDataAsync();
3await Task.WhenAll(task1, task2);

1public async Task GetDataAsync(CancellationToken ct)
2{
3    await Task.Delay(1000, ct);
4}