code: private static Stopwatch getRecentRunning(final Stopwatch parent) {
          if (null == parent) {
              return null;
          }
  
          final List<Stopwatch> leaves = parent.getLeaves();
  
          if (leaves.isEmpty()) {
              if (parent.isRunning()) {
                  return parent;
              } else {
                  return null;
              }
          }
  
          for (int i = leaves.size() - 1; i > -1; i--) {
              final Stopwatch leaf = leaves.get(i);
  
              if (leaf.isRunning()) {
                  return getRecentRunning(leaf);
              } else {
                  continue;
              }
          }
  
          return parent;
      }
docs: Gets the recent running stopwatch with the specified parent stopwatch.
  
  @param parent the specified parent stopwatch
  @return the recent stopwatch, returns {@code null} if not found