docs: public DocumentOperationResults optimizeChildren( final int targetCountPerBlock,
                                                        final int tolerance ) {
          Stopwatch sw = new Stopwatch();
          logger.info(JcrI18n.beginChildrenOptimization, getName());
          sw.start();
          
          DocumentOptimizer optimizer = new DocumentOptimizer(documentStore());
          try {
              DocumentOperationResults results = documentStore().localStore().performOnEachDocument((key, document) -> 
                  optimizer.optimizeChildrenBlocks(new NodeKey(key), document, targetCountPerBlock, tolerance)
              );
              sw.stop();
              logger.info(JcrI18n.completeChildrenOptimization, getName(), sw.getTotalDuration().toSimpleString(), results);
              return results;
          } catch (Throwable e) {
              logger.info(JcrI18n.errorDuringChildrenOptimization, getName(), sw.getTotalDuration().toSimpleString(), e);
          }
          return null;
      }