MutateState.cs

private void MutateState(Task task)
{
    var continuationWrapperType = Type.GetType("System.Runtime.CompilerServices.AsyncMethodBuilderCore+ContinuationWrapper");

    var taskAction = typeof(Task).GetField("m_action", BindingFlags.Instance | BindingFlags.NonPublic)
        .GetValue(task);

    Delegate func = task.AsyncState as Delegate ?? taskAction as Delegate;

    if (func?.Target?.GetType() == continuationWrapperType)
    {
        var continuationWrapper = func.Target;
    }
}