performance impact on read replicas during heavy vacuums on primary

[Dirk Krautschick]

Is there a scenario, where a very heavy vacuum on the primary side is 
affecting significantly
the read replica(s) in matter of performance (not the overall apply lag, 
which is expected) of
selects? I do not get this reproduced ...only the lag is clear but even 
hammering down the
primary with vaccum keeps my standby answering fine.
Cheers