Rc Rs Aa Synchronization

In the example below, database writes are concurrent at the points in time t1 and t2 and happen before a sync can communicate the changes. However, writes at times t4 and t6 are not concurrent as a sync happened in between.

Time	CRDB Instance1	CRDB Instance2
t1	SET key1 "a"
t2		SET key1 "b"
t3	— Sync —	— Sync —
t4	SET key1 "c"
t5	— Sync —	— Sync —
t6		SET key1 "d"