iOS UIManagedDocument锁定app block主线程

Question

我最近从一个离岸团队继承了一个代码库，我没有UIManagedDocument的经验。在某些情况下，首次安装应用程序时，初始化过程会完全锁定应用程序。它似乎与iCloud直接相关，因为当网络关闭时，应用程序立即加载。

我尝试在gcd块中执行此代码的各个部分，但是有一些进程仍然会转移到主线程并阻止所有输入。

无论如何要保存或异步打开？

NSURL *_url = [[self applicationDocumentDirectory] URLByAppendingPathComponent:MyDatabaseName];

self.document = [[MyCustomManagedDocument alloc] initWithFileURL:_url];
self.document.delegate = self;

NSMutableDictionary *options = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES],NSMigratePersistentStoresAutomaticallyOption,
                         [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption,nil];

NSURL *iCloudURL = [self iCloudDocumentsURL];
[options setObject:PrivateName forKey:NSPersistentStoreUbiquitousContentNameKey];
[options setObject:iCloudURL forKey:NSPersistentStoreUbiquitousContentURLKey];

self.document.persistentStoreOptions = options;

if ([[NSFileManager defaultManager] fileExistsAtPath:[_url path]]) {
    [self.document openWithCompletionHandler:^(BOOL success){
        if (success) {
            [self documentIsReady];
        }
    }];
}
else {
    // This can take 10 seconds sometimes.
    [self.document saveToURL:_url forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success){
        if (success) {
            [self documentIsReady];
        }
    }]; 
}