private static StringBuilder getTabs(TimerEvent.Timer timer) {
    StringBuilder tabs = new StringBuilder();
    while (timer.getParent().isPresent()) {
      tabs.append("\t");
      timer = timer.getParent().get();
    }
    return tabs;
  }
Gets a {@link StringBuilder} prepended with tabulation based on the number of parents {@code
timer} has.

@param timer the {@link TimerEvent.Timer} to base the tabulation on
@return a new {@link StringBuilder}
jib-plugins-common/src/main/java/com/google/cloud/tools/jib/plugins/common/TimerEventHandler.java