public static function resolveReal(string $path, string $workingDir = null)
    {
        if (null === $workingDir
        /**
         * Path includes full (absolute) path, which doesn't need
         * working directory.
         */
            && file_exists($real = Filesystem::resolve($path))) {
            return $real;
        } elseif (null !== $workingDir) {
        /**
         * ...Otherwise, add $workingDir before trying to find it.
         */
            $fullPath = Filesystem::slash($workingDir, $path);
            $real = Filesystem::resolve($fullPath);
            return file_exists($real) ? $real : null;
        }

        return null;
    }