This is the command invoked repeatedly to make the changes:
:%s/^\(.*\)|\%(\*\(\d\+\)\)\?$\n\1|\%(\*\(\d\+\)\)\?$/\=submatch(1)..'|*'..(max([str2nr(submatch(2)),1])+max([str2nr(submatch(3)),1]))/g
Problem: Peeking and flushing output slows down execution.
Solution: Do not update the mode message when global_busy is set. Do not
flush when only peeking for a character. (Ken Takata)
cb574f4154
Problem:
The sleep before collecting the initial screen state is confusing and
may lead to unexpected success if it comes after a blocking RPC call.
Solution:
Remove that sleep and add an "intermediate" argument.