log,time: improve performance for writing a line to a log, add Time.format_rfc3339_micro/0

[enghitalo]

v wipe-cache && v -prod crun log_.v > lala.log

Before

max_iterations: 1000000
SPENT  354.390 ms in log.info
SPENT  354.037 ms in log.error
SPENT   40.974 ms in println

After

max_iterations: 1000000
SPENT  171.269 ms in log.info
SPENT  171.246 ms in log.error
SPENT   38.279 ms in println

import log
import benchmark

const max_iterations := 1000000

fn main() {
	println('max_iterations: $max_iterations')

 	mut l := log.Log{}
	l.set_level(.info)
	l.set_full_logpath('./info.log')

	mut b := benchmark.start()

	for i := 0; i < max_iterations; i++ {
		l.info('Hello, World!')
	}

	b.measure('log.info')

	for i := 0; i < max_iterations; i++ {
		l.error('Hello, World!')
	}

	b.measure('log.error')

	for i := 0; i < max_iterations; i++ {
		println('Hello, World!')
	}
	b.measure('println')
}

*Note: if I remove time related format from log module

max_iterations: 1000000
SPENT   36.868 ms in log.info
SPENT   37.979 ms in log.error
SPENT   47.548 ms in println

*Note2: This was just a quick tweak I discovered out of curiosity. I'm not interested in making any major improvements right now, but there are several other tweaks and tests, such as using safe-threads when have logpath defined to log without interfering with the application's performance, and reusing time variables in some cases and managing cache.

_{Huly®: V_0.6-21111}

[enghitalo]

Write file in intervals should be good. like what happens here

pub fn (mut pv Picoev) serve() {
	spawn update_date_string(mut pv)

	for {
		pv.loop_once(1)
	}
}

// update_date updates the date field of the Picoev instance every second for HTTP headers
fn update_date_string(mut pv Picoev) {
	for {
		// get GMT (UTC) time for the HTTP Date header
		gmt := time.utc()
		pv.date = gmt.http_header_string()
		time.sleep(time.second)
	}
}

[spytheman]

Write file in intervals should be good. like what happens here

This is good for a web server, but not as a general default.

[spytheman]

With the latest changes, on my machine:

[spytheman]

The musl CI jobs are failing due to an unrelated problem, that is fixed in #22667 .