code: public FileWatcher register(final Path path, final Class<? extends FileEventHandler> handler,
        final Consumer<FileEventOptions> configurer) {
      return register(c -> path, p -> new FileEventOptions(p, handler), configurer);
    }
docs: Register the given directory tree and execute the given handler whenever a file/folder has been
  created, modified or delete. The configurer callback allow you to customize default event
  kinds, filter specific file types and restrict the watch scope lookup to direct files.
  
  @param path Directory to register.
  @param handler Handler to execute.
  @param configurer Configurer callback.
  @return This module.
  @see FileEventOptions