Choose the capacity to allocate for a buffer that needs to hold
requested instances. Grows by 1.5× to leave headroom for the next update
without a fresh grow — capped at MAX_CAPACITY_HEADROOM elements of slack,
so the factor does not scale into hundreds of wasted MiB on a very large
node — but never goes below currentMinInstanceCapacity (see
DEFAULT_MIN_INSTANCE_CAPACITY).
Choose the capacity to allocate for a buffer that needs to hold
requestedinstances. Grows by 1.5× to leave headroom for the next update without a fresh grow — capped atMAX_CAPACITY_HEADROOMelements of slack, so the factor does not scale into hundreds of wasted MiB on a very large node — but never goes belowcurrentMinInstanceCapacity(seeDEFAULT_MIN_INSTANCE_CAPACITY).