Why do you detect self == MMKV.class in initialize ?

[SeanChense]

+ (void)initialize {
	if (self == MMKV.class) {
		static dispatch_once_t onceToken;
		dispatch_once(&onceToken, ^{
			g_instanceDic = [NSMutableDictionary dictionary];
			g_instanceLock = [[NSRecursiveLock alloc] init];

			MMKVInfo(@"pagesize:%d", DEFAULT_MMAP_SIZE);
		});
	}
}

[lingol]

Nothing special, just something you should do when programming in Objective-C. initialize().