public static class FixedRateUtils
{

    public static void EnableFixedRateWithCatchUpCorrected(ComponentSystemGroup group, float timeStep)
    {
        var manager = new FixedRateCatchUpManagerCorrected(timeStep);
        group.UpdateCallback = manager.UpdateCallback;
    }

    public static void DisableFixedRate(ComponentSystemGroup group)
    {
        group.UpdateCallback = null;
    }

    internal class FixedRateCatchUpManagerCorrected
    {
        protected float m_FixedTimeStep;
        protected double m_LastFixedUpdateTime;
        protected int m_FixedUpdateCount;
        protected bool m_DidPushTime;
        internal FixedRateCatchUpManagerCorrected(float fixedStep)
        {
            m_FixedTimeStep = fixedStep;
        }
        internal bool UpdateCallback(ComponentSystemGroup group)
        {
            m_LastFixedUpdateTime = group.World.Time.ElapsedTime;
            m_FixedUpdateCount = 1;

            group.World.PushTime(new TimeData(
            elapsedTime: m_LastFixedUpdateTime,
            deltaTime: m_FixedTimeStep));

            group.UpdateCallback = this.InternalUpdateCallback;

            m_DidPushTime = true;
            return true;
        }

        internal bool InternalUpdateCallback(ComponentSystemGroup group)
        {
            // if this is true, means we're being called a second or later time in a loop
            if (m_DidPushTime)
            {
                group.World.PopTime();
            }

            var elapsedTime = group.World.Time.ElapsedTime;

            if (elapsedTime - m_LastFixedUpdateTime >= m_FixedTimeStep)
            {
                // Note that m_FixedTimeStep of 0.0f will never update
                m_LastFixedUpdateTime += m_FixedTimeStep;
                m_FixedUpdateCount++;
            }
            else
            {
                m_DidPushTime = false;
                return false;
            }

            group.World.PushTime(new TimeData(
                elapsedTime: m_LastFixedUpdateTime,
                deltaTime: m_FixedTimeStep));

            m_DidPushTime = true;
            return true;
        }
    }

}