What is the difference between Task.WhenAll and Task.WhenAny?

Question

Accepted Answer

**WhenAll** — wait for all. **WhenAny** — wait for first.

**WhenAll:**
- Wait for all tasks.
- Parallel execution.
- All results.

**WhenAny:**
- Wait for first.
- Race condition.
- First result.

```csharp
// WhenAll
var tasks = urls.Select(url => client.GetAsync(url));
var responses = await Task.WhenAll(tasks);

// WhenAny
var task1 = GetFromSource1();
var task2 = GetFromSource2();
var first = await Task.WhenAny(task1, task2);
```

**Key:** WhenAll for parallel, WhenAny for race.

C#: What is the difference between Task.WhenAll and Task.WhenAny?