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: main.rs
    path of file: ./repos/erooster/crates/erooster/src
    
    the code of the file until where you have to start completion: // SPDX-FileCopyrightText: 2023 MTRNord
//
// SPDX-License-Identifier: Apache-2.0

//! Erooster Mail Server
//!
//! Erooster is a rust native imap server bui
    
async fn cleanup(receiver: &Arc<Mutex<Receiver>>, shutdown_flag: &CancellationToken) {
    info!("Received ctr-c. Cleaning up");
    shutdown_flag.cancel();
    opentelemetry::global::shutdown_tracer_provider();
    {
        let mut lock = receiver.lock().await;

        info!("Gained lock. Saving queue");
        lock.save().expect("Unable to save queue");
        info!("Saved queue. Exiting");
    };
}