code: public void unregister(FileSubscriber fileSubscriber) {
          for (IdentificationSet<FileSubscriber> subList : fileSubscribers.values()) {
              subList.remove(fileSubscriber);
          }
          defaultFileSubscribers.remove(fileSubscriber);
      }
docs: Unregisters all instances of fileSubscriber found.
  
  @param fileSubscriber the fileSubscriber to unregister