code: function transformer(tree, file, next) {
      if (loadError) {
        next(loadError)
      } else if (config.checker) {
        all(tree, file, config)
        next()
      } else {
        queue.push([tree, file, config, next])
      }
    }
docs: Transformer which either immediately invokes `all` when everything has finished loading or queues the arguments.