public function getAllHashes(string $namespace): array
    {
        $directory = implode(DIRECTORY_SEPARATOR, [
            $this->directory,
            $namespace,
        ]);

        $result = [];
        if (is_dir($directory)) {
            $directoryIterator = new RecursiveDirectoryIterator(
                $directory,
                RecursiveDirectoryIterator::SKIP_DOTS
            );

            foreach (new RecursiveIteratorIterator($directoryIterator) as $file) {
                /* @var SplFileInfo $file */
                $result[] = $file->getFilename();
            }
        }
        return $result;
    }