histogram.go
func createHistogramBins(minExponent, maxExponent uint32) []int64 {
	var bins []int64
	for i := minExponent; i <= maxExponent; i++ {
		bins = append(bins, int64(1)<<i)
	}
	return bins
}
func createHistogramBins(minExponent, maxExponent uint32) []int64 {
	var bins []int64
	for i := minExponent; i <= maxExponent; i++ {
		bins = append(bins, int64(1)<<i)
	}
	return bins
}
// createHistogramBins creates bins for an histogram. The bin sizes are powers
// of two of the form [2^min_exponent, ..., 2^max_exponent].