KeyValueData

用来存储 Key-Value 型数据。可针对不同情况使用不同的后端存储。

Manage key-value data with same protocol, for kinds of backends.

LAST

Change ios.deployment_target to 11.0
Add iCloud as backend storage
- Note there is a limitation of iCloud data size, it is not for 'data' but configuration
Change impontanceLevel to 1 for all backend, this will cause sync() on every data set. You can still change this number

KeyChain with accessGroup will reload data before EVERY get / set
- to reduce data conflict between two sessions with same key/accessGroup
- technically, one session loads data between another session's loading & saving will still cause confliction. but we IDEALLY ASSUME that will not happen
- it affact performance a little, tachnically. KeyValueDictionaryInKeychain(withKey:) without accessGroup still use old methodlogy : read from cache, write through
- also, as you may know, you should never store big data to keychain

Enable accessGroup support for KeyChain
- public init(withKey: String, accessGroup: String)