Function plan_off_chip 

pub fn plan_off_chip(classes: &[StateClass], hbm_bytes: u64) -> Vec<TensorSpace>

★ THE NEXT TIER DOWN. Each class the SRAM does not hold goes, in the order plan_states ranks by, to its chip’s HBM while hbm_bytes holds it whole, and to the DDR (Dram) past it; with no HBM, all of it to the DRAM.