resetChunk

Starts a new chunk immediately, even if the current chunk has not reached numAdsDeduped. Subsequent loadAd calls are handled by the new chunk.

Ad loaders already requested or queued in the previous chunk keep being processed there. Responses still pending in the previous chunk are not applied to requests that the new chunk sends before those responses arrive. The duplication keys and advertiser domains accumulated by previous chunks (up to numAdsDeduped * 2 responses) are still applied to the new chunk.

Automatic rotation after numAdsDeduped requests still applies, so the requests after this call are split into multiple chunks when they exceed numAdsDeduped.

Calling this on a chunk with no ad requests yet is a no-op, so repeated calls are safe.