https://datatracker.ietf.org/doc/html/rfc1459#section-4.5.3
https://datatracker.ietf.org/doc/html/rfc2812#section-3.6.3
-- https://modern.ircdocs.horse/#whowas-message
and:
"At the end of all reply batches, there must be RPL_ENDOFWHOWAS
(even if there was only one reply and it was an error)."
-- https://datatracker.ietf.org/doc/html/rfc1459#page-50
-- https://datatracker.ietf.org/doc/html/rfc2812#page-45
and:
"Servers MUST reply with either ERR_WASNOSUCHNICK or [...],
both followed with RPL_ENDOFWHOWAS"
-- https://modern.ircdocs.horse/#whowas-message