When something happens apace, it happens quickly.

You are most likely to see the adverb apace describing some kind of work, and it's usually paired up with the verb continue. The literal meaning of the 14th century (1275–1325; Middle English), phrase a pace was "at a pace," or "at a good pace." The word of origin for apace is probably from Old French à pas, at a (good) pace

Definitions of apace /əˈpeɪs/ adverb

Swiftly, quickly, at a rapid pace, with rapid movements, at a quick pace, at a fast speed or pace, with great speed

keep/stay apace with : to go or advance at the same rate as (something): to keep up with

apace with : going or advancing at the same rate as (something)

abreast Used with of or with  trying to keep apace with changes in technology. In such a way or at such a speed as to keep up the requisite momentum

Synonyms: briskly, chop-chop, double-quick, fast, fleetly, full tilt, hastily, hell-for-leather, hot, lickety-split, posthaste, presto, pronto, quick, quickly, rapidly, snappily, soon, speedily, swift, swiftly

Words related to apace: immediately, promptly, readily, impetuously, impulsively, rashly, recklessly, abruptly, suddenly, energetically, vigorously