多线程下载或上传数据限速

public class SpeedLimit
    {
        private const int BalancerUp = 50;
        private const int BalancerDown = -75;

        private double _CurrentWait;
        private bool _Enabled;
        private double _MaxLimit;
        private OperationListControl _OperationListControl = null;
        public Func<double> CalcRate = null;

        public SpeedLimit()
        { }

        public void SetOperationListControl(OperationListControl control)
        {
            this._OperationListControl = control;
        }

        public double MaxLimit
        {
            get { return this._MaxLimit; }
            set
            {
                this._MaxLimit = value;
                if (this._MaxLimit == 0)
                    this._Enabled = false;
                else
                    this._Enabled = true;
            }
        }

        public void WaitFor()
        {
            if (this._Enabled && this._OperationListControl != null && this.CalcRate != null)
            {
                double totalRate = this.CalcRate();

                if (totalRate > this._MaxLimit)
                {
                    this._CurrentWait += BalancerUp;
                }
                else
                {
                    this._CurrentWait = Math.Max(this._CurrentWait + BalancerDown, 0);
                }

                Thread.Sleep((int)this._CurrentWait);

                Debug.WriteLine("TotalDownloadRate = " + totalRate);
                Debug.WriteLine("maxLimit = " + this._MaxLimit);
                Debug.WriteLine("currentWait = " + this._CurrentWait);
            }
        }
    }