Replica and transaction

Hi,

I found a statement:

Long-running transactions can cause replication lag because the changes made by these transactions are not replicated until the transaction is committed.
(https://www.percona.com/blog/replication-lag-in-postgresql/)


It means:
change made by transaction is not replicated until the transaction is committed?

And for example
time0: wal on primary
time1: tx1 begin
time2: tx2 begin
time3: tx2 rollback
time4: tx3 begin
time5: tx3 commit
time6: tx1 commit
time7: walsender sends tx1, tx3 to replica, tx2 skipped because rollback
?

br
Kaido