db_impl: Use a BufWriter inside LogWriter Unbuffered write-a-lot with 32768 entries written, first four iterations on a new DB: usr=0.32 sys=0.12 elap=0.46 usr=0.47 sys=0.12 elap=0.60 usr=0.59 sys=0.11 elap=0.72 usr=0.50 sys=0.15 elap=0.67 Buffered write-a-lot with 32768 entries written, first four iterations on a new DB: usr=0.22 sys=0.01 elap=0.24 (delta = -0.1/-0.11/-0.22) usr=0.43 sys=0.03 elap=0.48 (delta = -0.04/-0.09/-0.12) usr=0.54 sys=0.05 elap=0.62 (delta = -0.05/-0.06/-0.1) usr=0.42 sys=0.03 elap=0.47 (delta = (-0.08/-0.12/-0.2)

use std::thread;
use std::time;


pub fn micros() -> u64 {
    loop {
        let now = time::SystemTime::now().duration_since(time::UNIX_EPOCH);

        match now {
            Err(_) => continue,
            Ok(dur) => return dur.as_secs() * 1000000 + (dur.subsec_nanos() / 1000) as u64,
        }
    }
}

pub fn sleep_for(micros: u32) {
    thread::sleep(time::Duration::new(0, micros * 1000));
}