DelayedStart extension for System.Threading.Tasks.Task

TaskEx.cs

public static class TaskEx
{
    private static readonly ConcurrentDictionary<Task, Timer> Timers = new ConcurrentDictionary<Task, Timer>();

    public static Task DelayedStart(this Task task, TimeSpan delay)
    {
        var timer = new Timer(_ => Start(task), null, (long)delay.TotalMilliseconds, -1L);
        Timers.AddOrUpdate(task, timer, (k, t) => t);
        return task;
    }

    public static Task DelayedStart(Action action, TimeSpan delay)
    {
        return DelayedStart(new Task(action), delay);
    }

    public static Task DelayedStart(Action action, CancellationToken cancellationToken, TimeSpan delay)
    {
        return DelayedStart(new Task(action, cancellationToken), delay);
    }

    public static Task DelayedStart(Action action, CancellationToken cancellationToken, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task(action, cancellationToken, taskCreationOptions), delay);
    }

    public static Task DelayedStart(Action action, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task(action, taskCreationOptions), delay);
    }

    public static Task DelayedStart(Action<object> action, object state, TimeSpan delay)
    {
        return DelayedStart(new Task(action, state), delay);
    }

    public static Task DelayedStart(Action<object> action, object state, CancellationToken cancellationToken, TimeSpan delay)
    {
        return DelayedStart(new Task(action, state, cancellationToken), delay);
    }

    public static Task DelayedStart(Action<object> action, object state, CancellationToken cancellationToken, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task(action, state, cancellationToken, taskCreationOptions), delay);
    }

    public static Task DelayedStart(Action<object> action, object state, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task(action, state, taskCreationOptions), delay);
    }

    public static Task<T> DelayedStart<T>(this Task<T> task, TimeSpan delay)
    {
        var timer = new Timer(_ => Start(task), null, (long)delay.TotalMilliseconds, -1L);
        Timers.AddOrUpdate(task, timer, (k, t) => timer);
        return task;
    }

    public static Task<T> DelayedStart<T>(Func<T> func, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func), delay);
    }

    public static Task<T> DelayedStart<T>(Func<T> func, CancellationToken cancellationToken, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, cancellationToken), delay);
    }

    public static Task<T> DelayedStart<T>(Func<T> func, CancellationToken cancellationToken, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, cancellationToken, taskCreationOptions), delay);
    }

    public static Task<T> DelayedStart<T>(Func<T> func, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, taskCreationOptions), delay);
    }

    public static Task<T> DelayedStart<T>(Func<object, T> func, object state, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, state), delay);
    }

    public static Task<T> DelayedStart<T>(Func<object, T> func, object state, CancellationToken cancellationToken, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, state, cancellationToken), delay);
    }

    public static Task<T> DelayedStart<T>(Func<object, T> func, object state, CancellationToken cancellationToken, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, state, cancellationToken, taskCreationOptions), delay);
    }

    public static Task<T> DelayedStart<T>(Func<object, T> func, object state, TaskCreationOptions taskCreationOptions, TimeSpan delay)
    {
        return DelayedStart(new Task<T>(func, state, taskCreationOptions), delay);
    }

    private static void Start(Task task)
    {
        task.Start();

        Timer timer;
        if (!Timers.TryRemove(task, out timer)) return;
        using (timer)
        {
            // Just disposing
        }
    }
}

This is quite handy, so I've stuck it here for pasting in where it's needed.