making stores and their users fully async requires all data streams to
be async. the most notable data streams in common usage are curl first
and remote stores second. curl is much more contained today and easier
to asyncify (with the preparatory work we've done in the past commits)
Change-Id: I2d6ff4687ee2b47e4efaa6714827b7283bed941d
eldritch horrors
1729c8ca3e