verify checksums online

i should know the answer to this... but asking anyway

i think there had been some mailing list discussions years ago? the
pg_checksum utility in core still can't do an online check right?

looking around, i think that michael's pg_checksums_ext still seems to
be available in debian repos, and it advertises online checks, which
makes me think that the core pg_checksum might still not have merged
any code for online checking yet

but i wanted to confirm with someone - my easiest options for online
verifying checksums would be to trigger pg_basebackup then check
pg_stat_database, or to install michael's utility?

-Jeremy