code: private void addDependent(String pathName, String relativeTo) {
          if (relativeTo != null) {
              Set<String> dependents = dependenctRelativePaths.get(relativeTo);
              if (dependents == null) {
                  dependents = new HashSet<String>();
                  dependenctRelativePaths.put(relativeTo, dependents);
              }
              dependents.add(pathName);
          }
      }
docs: Must be called with pathEntries lock taken