Attempt at reservation pattern

reservation-pattern

public class FooReserver
{
    private readonly int reserveFor;

    public static List<string> ReservedFoos = new List<string>();

    public FooReserver(int reserveFor)
    {
        this.reserveFor = reserveFor;
    }

    public void Reserve(string fooName)
    {
        if (ReservedFoos.Contains(fooName))
        {
            throw new NameIsReservedException();
        }

        ReservedFoos.Add(fooName);
        Task.Run(() =>
        {
            Task.Delay(this.reserveFor);
            ReservedFoos.Remove(fooName);
        });
    }
}