Major Description
KIP-392 adds high watermark propagation to followers as a means to better sync up followers HW with leader. The issue we have noticed after trying out 2.4.0 and 2.4.1 is a spike in fetch request rate in the default selector case (leader), that does not really require this high watermark propagation:
This spike causes an increase in resource allocation (CPU) on the brokers.
An easy solution would be to disable this propagation (at least) for the default leader selector case to improve the backward compatibility.
