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/zenoh-flow/zfctl/src
    
    the code of the file until where you have to start completion: //
// Copyright (c) 2021 - 2024 ZettaScale Technology
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
//
// Contributors:
//   ZettaScale Zenoh Team, <zenoh@zettascale.tech>
//

mod in
    
async fn main() -> Result<()> {
    // TODO Configure tracing such that:
    // - if the environment variable RUST_LOG is set, it is applied,
    // let a = std::env::var(tracing_subscriber::EnvFilter::DEFAULT_ENV);
    // - otherwise, provide a default that will only log INFO or above messages, for zfctl only.
    let _ = tracing_subscriber::fmt::try_init();

    let zfctl = Zfctl::parse();

    let session = zenoh::open(zenoh::config::peer())
        .res()
        .await
        .map_err(|e| anyhow!("Failed to open Zenoh session:\n{:?}", e))?;

    match zfctl.command {
        Command::Instance { command, runtime } => {
            let orchestrator_id = match runtime {
                Some(id) => id,
                None => {
                    let mut runtimes = get_all_runtimes(&session).await?;
                    let orchestrator =
                        runtimes.remove(rand::thread_rng().gen_range(0..runtimes.len()));
                    tracing::trace!(
                        "Orchestrator: < {} > (id: {})",
                        orchestrator.name,
                        orchestrator.id
                    );

                    orchestrator.id
                }
            };

            command.run(session, orchestrator_id).await
        }
        Command::Runtime(r) => r.run(&session).await,
    }
}