potential speed improvement for repeated string concatenation

[BCS]

Reply to Tristam,

> How do these perform in a multi-threaded scenario? At a glance, I
> would guess these suffer from much the same problems as COW.
> 
> Witold Baryluk Wrote:
> 
>

If I had to guess... It looks like it never modifies data, just makes references 
to it: Copy reference, replace reference on write. As long as you can get 
the memory back that should be fast (and lock free to boot).