[tz] Fractional seconds in zic input

[Steve Allen]

On Mon 2018-02-05T10:38:56-0800 Paul Eggert hath writ:
> I guess I'm not seeing the harm to go with nanoseconds in the data format;
> if a downstream user wants less precision they can easily round. And
> following Steve Allen's lead, we can mention in the documentation that
> there's no practical use of sub-millisecond precision in these old
> timestamps.

There are serious questions that need context to inform the choices
of IANA tz when looking at sub-second precision.

I ask that everyone take a look at this writeup and the questions
that it poses for what tz database really wants to encode.

https://www.ucolick.org/~sla/temporary/tzfracsec/

--
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