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: mod.rs
    path of file: ./repos/rumqtt/rumqttd/src/segments
    
    the code of the file until where you have to start completion: use crate::Offset;
use std::usize;
use std::{collections::VecDeque, io};

mod segment;
pub mod utils;

use segment::{Segment, SegmentPosition};
use tracing::warn;

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum Position {
    Next { start: (u64, u64), end: (u64, u64) },
    Done { start: (u64, u64), end: (u64, u64) },
}

pub trait Storage {
    fn size(&self) -> usize;
}

/// There are 2 limits which are enforced:
/// - limit on size of each segment created by this log in bytes
/// - limit on number of segments in memory
///
/// When the active_segment is filled up, we move it to memory segments and empty it for new logs.
/// When the limit on the number of memory segments is reached, we remove the oldest segment from
/// memory segment
    
    fn read_jump_from_deleted_segment_works() {
        let max_segment_size = 1024 * 10; // 10K
        let packet_size: u64 = 1024;
        // 1 as active, 9 as inactive but in mem
        let mut log = CommitLog::new(max_segment_size, 10).unwrap();

        // Fill all 10 in memory segments
        for i in 0..100 {
            log.append(random_payload(i, packet_size));
        }
        assert_eq!(log.head, 0);
        assert_eq!(log.tail, 9);

        let mut out = Vec::new();
        let next = log.readv((0, 0), 5, &mut out).unwrap();
        assert_eq!(
            next,
            Next {
                start: (0, 0),
                end: (0, 5)
            }
        );

        // Fill 10 more inmemory segment pushing previous into retention policy
        for i in 0..100 {
            log.append(random_payload(i, packet_size));
        }
        assert_eq!(log.head, 10);
        assert_eq!(log.tail, 19);

        let next = log.readv((0, 0), 5, &mut out).unwrap();
        assert_eq!(
            next,
            Next {
                start: (10, 100),
                end: (10, 105)
            }
        );
    }