//AFNetworkReachabilityManager中的单例,省略了其他代码
@interface AFNetworkReachabilityManager : NSObject

  + (instancetype)sharedManager;

@end

@implementation AFNetworkReachabilityManager

+ (instancetype)sharedManager {
    static AFNetworkReachabilityManager *_sharedManager = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _sharedManager = [self manager];
    });

    return _sharedManager;
}

@end

class GofUserSession
{
    static let shareInstance = GofUserSession();
    
    private init() {}
    
}