You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tempo_track.rs
    path of file: ./repos/Neothesia/midi-file/src
    
    the code of the file until where you have to start completion: use midly::{MetaMessage, TrackEvent, TrackEventKind};
use std::{collections::HashMap, sync::Arc, time::Duration};

#[derive(Debug, Clone)]
pub struct Tempo
    
fn pulse_to_duration(pulses: u64, tempo: u32, pulses_per_quarter_note: u16) -> Duration {
    let u_time = pulses as f64 / pulses_per_quarter_note as f64;
    // We floor only because Synthesia floors,
    // so if we want to test for timing regresions we have to do the same
    let time = (u_time * tempo as f64).floor() as u64;
    Duration::from_micros(time)
}