message: Prettify time.
diff: @@ -11,7 +11,7 @@ use libtock::timer::Duration;
  #[libtock::main]
  async fn main() -> TockResult<()> {
  - const DELAY_MS: isize = 50;
  + const DELAY_MS: usize = 50;
  let mut console = Console::new();
  let mut previous_ticks = None;
  @@ -23,16 +23,41 @@ async fn main() -> TockResult<()> {
  let frequency = timer.clock_frequency().hz();
  writeln!(
  console,
  - "[{}] Waited {} ms. Now is {:#010x} ticks ({} ticks since last time at {} Hz)",
  + "[{}] Waited {:?}. Now is {:#010x} ticks ({:?} ticks since last time at {} Hz)",
  i,
  - i * DELAY_MS,
  + PrettyTime::from_ms(i * DELAY_MS),
  ticks,
  previous_ticks.map(|previous| ticks - previous),
  frequency
  )?;
  previous_ticks = Some(ticks);
  - timer::sleep(Duration::from_ms(DELAY_MS)).await?;
  + timer::sleep(Duration::from_ms(DELAY_MS as isize)).await?;
  }
  Ok(())
  }
  +
  +struct PrettyTime {
  + mins: usize,
  + secs: usize,
  + ms: usize,
  +}
  +
  +impl PrettyTime {
  + fn from_ms(ms: usize) -> PrettyTime {
  + PrettyTime {
  + ms: ms % 1000,
  + secs: (ms / 1000) % 60,
  + mins: ms / (60 * 1000),
  + }
  + }
  +}
  +
  +impl core::fmt::Debug for PrettyTime {
  + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
  + if self.mins != 0 {
  + write!(f, "{}m", self.mins)?
  + }
  + write!(f, "{}.{:03}s", self.secs, self.ms)
  + }
  +}
  