src/Router.php
private function _toClosure(callable &$callback) {
        if (!($callback instanceof \Closure))
            $callback = \Closure::fromCallable($callback);
        $callback = \Closure::bind($callback, $this, self::_getNamespace().'\\RouterWrapper');
    }
private function _toClosure(callable &$callback) {
        if (!($callback instanceof \Closure))
            $callback = \Closure::fromCallable($callback);
        $callback = \Closure::bind($callback, $this, self::_getNamespace().'\\RouterWrapper');
    }
将回调函数转换为闭包并绑定当前路由实例

@param callable $callback