investigating IO objects as a memory safe alternative to wrapping Array

[ExpandingMan]

It has been suggested on discourse that I should be using IO objects, which may essentially already do what would be required from reinterpret for performant IO. I definitely need to do some benchmarking to see if this is feasible.

My first worry is that read essentially has @noinline so this gives me some doubts about how performant it could be to embed in getindex methods.