code: void removeAll(BaseRow sortKey) {
  		Collection<BaseRow> list = treeMap.get(sortKey);
  		if (list != null) {
  			currentTopNum -= list.size();
  			treeMap.remove(sortKey);
  		}
  	}
docs: Removes all record list from the buffer under the sortKey.
  
  @param sortKey key to remove