字符串（contentsOfFile）泄漏

Question

我在仪器的泄漏中运行我们的应用程序，它检测到String(contentsOfFile)泄漏。

我们的应用程序中有此类：

class CoordinatesUtil {
    static let shared = CoordinatesUtil()

    private init() {
        for filename in ["group_one", "group_two", "group_three"] {
            loadFromCsv(filename)
        }
    }

    private func loadFromCsv(_ filename: String) -> [[String]]? {
        guard let path = Bundle.main.path(forResource: filename, ofType: "csv") else {
            return nil
        }

        do {
            let content = try String(contentsOfFile: path)
            let lines = content.components(separatedBy: CharacterSet.newlines)
                .map({$0.components(separatedBy: ",")})
                .filter({$0.count == 6})
            return lines
        } catch  {
            return nil
        }
    }
}

然后在我们的AppDelegate中将其初始化如下：

class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Initialize CoordinatesUtil
        DispatchQueue.global().async {
            let _ = CoordinatesUtil.shared
        }
    }
}

注意：CSV文件的内容包含从500到7K坐标的行。

有人知道为什么String(contentsOfFile)在这里泄漏吗？