ExponentialHistogram
data class ExponentialHistogram(val key: MetricKey, val scale: Int, val count: Long, val zeroCount: Long, val zeroThreshold: Double, val positiveOffset: Int, val positiveBucketCounts: List<Long>, val negativeOffset: Int, val negativeBucketCounts: List<Long>, val startEpochNanos: Long, val timeEpochNanos: Long) : MetricPoint
A quantile sketch rendered as an OTLP ExponentialHistogramDataPoint (cumulative temporality — the backing us.tractat.kuilt.crdt.DDSketch is grow-only).
Bucket layout is OTLP's: bucket j of a sign's array counts values whose magnitude is in (base^(offset+j), base^(offset+j+1)] with base = 2^(2^−scale). sum/min/max are not carried — a DDSketch does not track them, and they are optional in OTLP.