/** Returns ~2x the old capacity if small; ~1.5x otherwise. */
private int calculateNewCapacity() {
int oldCapacity = queue.length;
int newCapacity =
(oldCapacity < 64) ? (oldCapacity + 1) * 2 : IntMath.checkedMultiply(oldCapacity / 2, 3);
return capAtMaximumSize(newCapacity, maximumSize);
}