leftLen, rightLen := mid-a, b-mid
		balanceThreshold := length / 8
		if leftLen < rightLen {
			wasBalanced = leftLen >= balanceThreshold
			pdqsort_func(data, a, mid, limit)
			a = mid + 1
		} else {
			wasBalanced = rightLen >= balanceThreshold
			pdqsort_func(data, mid+1, b, limit)
			b = mid
		}
	}
}

// partition_func does one quicksort partition.
// Let p = data[pivot]