private static void Log(Task task) =>
    task.ContinueWith(t => Log(t.Exception),
        CancellationToken.None,
        TaskContinuationOptions.OnlyOnFaulted | TaskContinuationOptions.ExecuteSynchronously,
        TaskScheduler.Default);

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using System;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;

[MemoryDiagnoser]
public class Program
{
    static void Main(string[] args) => BenchmarkSwitcher.FromAssemblies(new[] { typeof(Program).Assembly }).Run(args);

    const int Iters = 1_000_000;

    private AsyncTaskMethodBuilder[] tasks = new AsyncTaskMethodBuilder[Iters];

    [IterationSetup]
    public void Setup()
    {
        Array.Clear(tasks, 0, tasks.Length);
        for (int i = 0; i < tasks.Length; i++)
            _ = tasks[i].Task;
    }

    [Benchmark(OperationsPerInvoke = Iters)]
    public void Cancel()
    {
        for (int i = 0; i < tasks.Length; i++)
        {
            tasks[i].Task.ContinueWith(_ => { }, CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted | TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
            tasks[i].SetResult();
        }
    }

    [Benchmark(OperationsPerInvoke = Iters)]
    public void Execute()
    {
        for (int i = 0; i < tasks.Length; i++)
        {
            tasks[i].Task.ContinueWith(_ => { }, CancellationToken.None, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
            tasks[i].SetResult();
        }
    }
}