docs: public static void start(final String taskTitle) {
          Stopwatch root = STOPWATCH.get();
  
          if (null == root) {
              root = new Stopwatch(taskTitle); // Creates the root stopwatch
              STOPWATCH.set(root);
  
              return;
          }
  
          final Stopwatch recent = getRecentRunning(STOPWATCH.get());
  
          if (null == recent) {
              return;
          }
  
          recent.addLeaf(new Stopwatch(taskTitle)); // Adds sub-stopwatch
      }