Add document about the lock of AbstractMessageGroupStore

Author: NaccOll

src/reference/antora/modules/ROOT/pages/message-store.adoc

@@ -158,3 +158,12 @@ It also allows the end marker to arrive at the aggregator before all the other r
 
 In addition, for configuration convenience, a `GroupConditionProvider` contract has been introduced.
 The `AbstractCorrelatingMessageHandler` checks if the provided `ReleaseStrategy` implements this interface and extracts a `conditionSupplier` for group condition evaluation logic.
+
+[[use-lock-registry]]
+== Use LockRegistry
+
+Starting with version 6.5, the `MessageStore` abstraction operate the metadata of message group with lock.
+This lock acquires the groupId and generated by `LockRegister`.
+Its purpose is to operate on the atomicity of messages and message groups.
+In multiple threads, adding or removing messages or updating metadata at the same time, some implementations may have message group errors if the lock is missing.
+By default, `LockRegister` uses `DefaultLockRegistry`, and developers can set it to the implementation they need through `setLockRegistry`