public void ExactlyWhatYouAreNotSupposedToDo()
{
// i r ImmutableArray<T>.Builder nao, look at me
ulong[] origBuf = { 1, 2, 3, 4 };
ImmutableArray <ulong> fakeImmutableBuf = origBuf.AsImmutableArrayDangerous();
// we should get the same values.
Assert.Equal(origBuf, fakeImmutableBuf);
// it should also be exactly the same instance... this MUST be copy-free, or else it's
// not worth it.
Assert.Same(origBuf, fakeImmutableBuf.AsRegularArrayDangerous());
// this is exactly what you're not supposed to do.
++origBuf[2];
Assert.Equal(origBuf, fakeImmutableBuf);
}