fn split_nanos_to_micros(nanos: u32) -> (bool, u32)Expand description
Splits a sub-second nanosecond count into a whole-second carry and the microsecond fraction to render, rounding half away from zero.
The returned fraction is always below one second, so it can never be written
as a fractional field of more than six digits. Only a nanosecond count of
.9999995 or more produces a carry.
chrono spells a leap second as a nanosecond count of one second or more, and
its %S already accounts for that, rendering 60 on a second-of-minute of
59 and folding into the next second elsewhere. The leap second is therefore
already in the seconds field and only the part below one second is ours to
write.