Is your feature request related to a problem? Please describe.
While bash and zsh have timers that provide µs precision, fish does not. This means that every command that finishes in less than a second will say something like: 23ms 0µs. Because everything is 0µs for the microseconds, that doesn't provide any additional information and just ends up needlessly expanding the prompt.

Describe the solution you'd like
An optional argument on the command line of -duration-low-precision to indicate that the command duration timer is low precision, or maybe you just don't want to see µs in your other shells.

Describe alternatives you've considered
I have a patch to completely remove µs that I've been maintaining for a couple of months, but I realize that a command line flag might be better here.

Additional context
Here's an output of the proposed patch showing just the duration module (and using the default fish prompt for clarity):