conversion from UTCTime helper

[simonmichael]

I hesitate to suggest this, since old-time's last release was in 2014. But as I understand it we all still require and use it, despite the name. So,

Here is a conversion I have more than once struggled to find or invent; I imagine I'm not the only one. Should it be added ?

utcTimeToClockTime :: UTCTime -> ClockTime
utcTimeToClockTime utc = TOD posixsecs picosecs
  where
    (posixsecs, frac) = properFraction $ utcTimeToPOSIXSeconds utc
    picosecs = round $ frac * 1e12