CancellationTokenSource.CreateLinkedTokenSource won't cancel peer tokens.

CreateLinkedTokenSource.cs

using System.Diagnostics;

var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(1));
var observer = new CancellationTokenSource();

var linked = CancellationTokenSource.CreateLinkedTokenSource(timeout.Token, observer.Token);

await Task.Run(async () => {
    try 
    {
        await Task.Delay(TimeSpan.FromSeconds(5), linked.Token);
        throw new InvalidOperationException("Operation should be cancelled before");
    }
    catch (OperationCanceledException)
    {
        Console.WriteLine($"Timeout token cancelled: {timeout.Token.IsCancellationRequested}");
        Console.WriteLine($"Observer token cancelled: {observer.Token.IsCancellationRequested}");

        Debug.Assert(!observer.Token.IsCancellationRequested);
    }
})