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/gyroflow/src/core/imu_integration
    
    the code of the file until where you have to start completion: // SPDX-License-Identifier: GPL-3.0-or-later
// Copyright Â© 2021-2022 Adrian <adrian.eddy at gmail>

mod complementary_v2;
mod complementary;
mod vqf;

use std::collections::BTreeMap;
use nalgebra::*;
use super::gyro_source::{TimeIMU, Quat64, TimeQuat};
use ahrs::{Ahrs, Madgwick, Mahony};

// TODO: Magnetometer calculations are disabled in Complementary and VQF. Figure out what's wrong and enable them

pub trait GyroIntegrator {
    fn integrate(imu_data: &[TimeIMU], duration_ms: f64) -> TimeQuat;
}

pub struct QuaternionConverter { }
pub struct ComplementaryIntegrator { }
pub struct VQFIntegrator { }
pub struct SimpleGyroIntegrator { }
pub struct SimpleGyroAccelIntegrator { }
pub struct MahonyIntegrator { }
pub struct MadgwickIntegrator { }

// const RAD2DEG: f64 = 180.0 / std::f64::consts::PI;
const DEG2RAD: f64 = std::f64::consts::PI / 180.0;

impl QuaternionConverter {
    pub fn convert(method: i32, org_quaternions: &TimeQuat, image_orientations : &TimeQuat, imu_data: &[TimeIMU], duration_ms: f64) -> TimeQuat {
        let integrated_quats = match method {
  
    
    fn integrate(imu_data: &[TimeIMU], duration_ms: f64) -> TimeQuat {
        if imu_data.is_empty() { return BTreeMap::new(); }

        let mut quats = BTreeMap::new();
        let init_pos = UnitQuaternion::from_euler_angles(std::f64::consts::FRAC_PI_2, 0.0, 0.0);
        let sample_time_s = duration_ms / 1000.0 / imu_data.len() as f64;

        let mut ahrs = Mahony::new_with_quat(sample_time_s, 0.5, 0.0, init_pos);
        let mut prev_time = imu_data[0].timestamp_ms - sample_time_s;
        for v in imu_data {
            if let Some(g) = v.gyro.as_ref() {
                let gyro = Vector3::new(-g[1], g[0], g[2]) * (std::f64::consts::PI / 180.0);
                let mut a = v.accl.unwrap_or_default();
                if a[0].abs() == 0.0 && a[1].abs() == 0.0 && a[2].abs() == 0.0 { a[0] += 0.0000001; }
                let accl = Vector3::new(-a[1], a[0], a[2]);

                *ahrs.sample_period_mut() = (v.timestamp_ms - prev_time) / 1000.0;

                if let Some(m) = v.magn.as_ref() {
                    let magn = Vector3::new(-m[1], m[0], m[2]);

                    match ahrs.update(&gyro, &accl, &magn) {
                        Ok(quat) => { quats.insert((v.timestamp_ms * 1000.0) as i64, *quat); },
                        Err(e) => log::warn!("Invalid data! {} Gyro: [{}, {}, {}] Accel: [{}, {}, {}] Magn: [{}, {}, {}]", e, gyro[0], gyro[1], gyro[2], accl[0], accl[1], accl[2], magn[0], magn[1], magn[2])
                    }
                } else {
                    match ahrs.update_imu(&gyro, &accl) {
                        Ok(quat) => { quats.insert((v.timestamp_ms * 1000.0) as i64, *quat); },
                        Err(e) => log::warn!("Invalid data! {} Gyro: [{}, {}, {}] Accel: [{}, {}, {}]", e, gyro[0], gyro[1], gyro[2], accl[0], accl[1], accl[2])
                    }
                }
                prev_time = v.timestamp_ms;
            }
        }

        quats
    }