recordHistogram

Record one measurement value into the histogram for key. A new series starts from histogramPrototype, so every series shares the cluster-wide configuration. Returns MetricExportResult.Success after the durable write.

No double-count under merge-retry. The per-bucket counts are per-replica GCounter slots, so re-merging the same remote snapshot never inflates them. Sequential recordHistogram calls each do count — the correct cumulative distribution semantics.

Throws