// NewTimingHistogram returns an object which is TimingHistogram-like. However, nothing
// will be measured until the histogram is registered in at least one registry.
func NewTimingRatioHistogram(opts *TimingRatioHistogramOpts) *TimingRatioHistogram {
	return NewTestableTimingRatioHistogram(time.Now, opts)
}

// NewTestableTimingHistogram adds injection of the clock