DROP_NEWEST

Drop the newest entry when the buffer is full.

Accounted for either way — WarpSpanExporter logs each drop, WarpLogRecordExporter counts refusals on ExporterHealth.refused. See the enum KDoc.

"Newest" is resolved per exporter, and the two shipped exporters resolve it differently: WarpSpanExporter evicts the newest buffered span and admits the arrival; WarpLogRecordExporter refuses the arrival, which at a full buffer is the newest record there is. See each exporter's KDoc.

Neither policy is the thing that bounds the total, and choosing this one does not exempt a replica from the other half. Refusing the arrival means a saturated WarpLogRecordExporter appends no op on the export path — but WarpLogRecordExporter.merge folds a peer's log in wholesale whatever the policy, and what a peer wrote cannot fold into this replica's compaction floor. So a gossiping replica still accumulates a small suppression record per foreign record windowed away, under either policy. See WarpLogRecordExporter's KDoc for the two-arm shape.