public class Bench73
    {
        public int[] _a = new int[100_000];

        [Benchmark(Baseline = true)]
        [MethodImpl(MethodImplOptions.NoInlining)]
        public void A()
        {
            for (int i = 0; i < 10000; i++)
                _a[1] = 100;
        }

        [Benchmark()]
        [MethodImpl(MethodImplOptions.NoInlining)]
        public void B()
        {
            for (int i = 0; i < 10000; i++)
                _a[10000] = 100;
        }
    }