public T offerReturnDropped(T item, int incrementCount) {
    return offerReturnAll(item, incrementCount).right;
  }
@param item stream element (<i>e</i>)
@return item dropped from summary if an item was dropped, null otherwise
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/aggregation/approximate/StreamSummary.java