Timed Queue with interface as callback

TimedQueue.cs

using System.Collections.Generic;
using System.Diagnostics;

namespace Utils
{
    public interface TimedQueueCallback
    {
        void OnMessage(string message);
        void OnEmpty();
    }

    public class TimedQueue
    {
        private float _dequeueTimer;
        private readonly float _dequeueDelay;

        private float _emptyTimer;
        private readonly float _emptyDelay;

        private readonly Queue<string> _messageQueue = new Queue<string>();

        private TimedQueueCallback _callback;

        public TimedQueue(TimedQueueCallback callback, float dequeueDelay = 0.5f, float emptyDelay = 2.0f)
        {
            _callback = callback;

            _dequeueDelay = dequeueDelay;
            _dequeueTimer = dequeueDelay + 0.1f;

            _emptyDelay = emptyDelay;
            _emptyTimer = _emptyDelay + 0.1f;
        }

        public void Update(float deltaTime)
        {
            if (_messageQueue.Count > 0)
            {
                _emptyTimer = 0;
                if (_dequeueTimer > _dequeueDelay)
                {
                    _callback.OnMessage(_messageQueue.Dequeue());
                    _dequeueTimer = 0;
                }
                _dequeueTimer += deltaTime;
            }
            else
            {
                if (_emptyTimer < _emptyDelay)
                {
                    _emptyTimer += deltaTime;
                    if (_emptyTimer > _emptyDelay)
                    {
                       _callback.OnEmpty();
                    }
                }
            }
        }

        public void Enqueue(string t)
        {
            _messageQueue.Enqueue(t);
            _emptyTimer = 0.0f;
        }
    }
}