using System.Runtime.CompilerServices;

long[] a = new long[100];
ref long misalignedLong = ref Unsafe.As<byte, long>(
    ref Unsafe.Add(ref Unsafe.As<long, byte>(ref a[0]), 1));
Test(ref misalignedLong);

[MethodImpl(MethodImplOptions.NoInlining)]
long Test(ref long misalignedLong) => Volatile.Read(ref misalignedLong);