on rust reference book this reduces total allocs from 490mb to 474mb:
==23272== Total: 490,538,699 bytes in 1,760,117 blocks
==23272== At t-gmax: 13,872,954 bytes in 4,655 blocks
==23272== At t-end: 488,516 bytes in 884 blocks
==23272== Reads: 830,509,060 bytes
==23272== Writes: 522,290,614 bytes
to
==40876== Total: 474,156,323 bytes in 1,521,025 blocks
==40876== At t-gmax: 13,872,954 bytes in 4,655 blocks
==40876== At t-end: 488,516 bytes in 884 blocks
==40876== Reads: 820,933,434 bytes
==40876== Writes: 514,838,350 bytes
573b6522f9