Re: Exposing subsecond precision in current-seconds

[Lassi Kortela]

The trouble with procedure names of the form `current-*seconds` is that 
it's not clear whether they return an integer or a float. And in the 
case of a float, which subdivision of time is represented by the integer 
part.

E.g. does `current-microseconds` return an integer number of 
microseconds, or does it return a float whose integer part is full 
seconds and the fractional part is partial seconds sourced from a 
roughly microsecond-precision timer? Same concern with 
`current-milliseconds` and `current-nanoseconds`.

`current-timespec` would be simple enough since timespecs are formally 
defined in SRFI 174 (and also defined by POSIX "struct timespec" to have 
nanosecond precision). I appreciate that there's also a need for 
procedures that return int/float times, but naming those well is not as 
simple.

See also SRFI 120 (Timer APIs). 
<https://srfi.schemers.org/srfi-120/srfi-120.html>