let's say a record have column a, b, c three columns,
at one changepoint, on device A, data was updated twice:
1. update b = 1
2. update c = 2
When fetchChange on device B, what will it get? one change or two changes? (during the change, deviceB was offline and startup)
Will it get the partial change record or the whole record?
During the test, sometimes, I got two changes, and sometimes I just got one change (maybe it is the consolidated final change?)
why is it not consistent?
