Comment by rntz

> If you are hell-bent on using FixedBufferAllocator only and you want to avoid copies, there is a way. Using two buffers (and separate allocators backed by them), it is possible to keep swapping between them after every iteration.

I found this bit lovely: the author has independently reinvented the core idea of semispace copying garbage collectors (see eg https://wingolog.org/archives/2022/12/10/a-simple-semi-space...).