斯威夫特＆amp; Objective-c使用AFNetwork崩溃

Question

请求数据时，偶尔会崩溃。 我不知道AFNetworking是问题还是我的代码问题。

 - (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(__unused id)object
                        change:(NSDictionary *)change
                       context:(void *)context
{
    if (context == AFHTTPRequestSerializerObserverContext) {
        if ([change[NSKeyValueChangeNewKey] isEqual:[NSNull null]]) {
            [self.mutableObservedChangedKeyPaths removeObject:keyPath];
        } else {
            [self.mutableObservedChangedKeyPaths addObject:keyPath];
        }
    }
}