Task based sequencer

Sequencer V1

using System;
using System.Threading.Tasks;

namespace Seq
{
    public class Sequencer
    {
        private readonly object _lock = new object();
        private Task _task = Task.FromResult(0);

        public void Dispatch(Action action)
        {
            lock (_lock)
            {
                _task = _task.ContinueWith(_ => action());
            }
        }
    }
}