Elapsed prints how long an operation took, as "(label took 1.234s)", so
a slow install can be attributed to a step from its log alone. Use it as
`defer log.Elapsed(time.Now(), "ko resolve")`: the start time is captured
when the defer statement runs.
Step announces a named install step. It takes a plain string rather than a
format because most step names are computed (a demo name plus a suffix, a
namespace/name pair), and a stray % in one of those should not be read as a
verb.