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: range_tracker.rs
    path of file: ./repos/neqo/neqo-transport/benches
    
    the code of the file until where you have to start completion: // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use criterion::{criterion_group, crite
    
fn build_coalesce(len: u64) -> RangeTracker {
    let mut used = RangeTracker::default();
    used.mark_acked(0, CHUNK as usize);
    used.mark_sent(CHUNK, END as usize);
    // leave a gap or it will coalesce here
    for i in 2..=len {
        // These do not get immediately coalesced when marking since they're not at the end or start
        used.mark_acked(i * CHUNK, CHUNK as usize);
    }
    used
}