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: pam.rs
    path of file: ./repos/aws-sdk-rust/examples/cross_service/photo_asset_management/src/bin
    
    the code of the file until where you have to start completion: // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
use photo_asset_management::{
    common::{init_tracing_subscriber, Common},
    handlers::{detect_labels, download, hello, labels, upload},
};
use tracing::log::info;

#[tokio::main]
async fn main() -> Result<(), lambda_runtime::Error> {
    init_tracing_subscriber();

    info!("tracing_subscriber initialized");

    let common = Common::load_from_env().await;

    let handler = std::env::var("_HANDLER").expect("_
    
async fn main() -> Result<(), lambda_runtime::Error> {
    init_tracing_subscriber();

    info!("tracing_subscriber initialized");

    let common = Common::load_from_env().await;

    let handler = std::env::var("_HANDLER").expect("_HANDLER provided");

    info!("Using handler {handler}");

    match handler.as_str() {
        "detect_labels" => {
            lambda_runtime::run(lambda_runtime::service_fn(|request| async {
                detect_labels::handler(&common, request).await
            }))
            .await
        }
        "download" => {
            lambda_runtime::run(lambda_runtime::service_fn(|request| async {
                download::handler(&common, request).await
            }))
            .await
        }
        "labels" => {
            lambda_runtime::run(lambda_runtime::service_fn(|request| async {
                labels::handler(&common, request).await
            }))
            .await
        }
        "hello" => {
            lambda_runtime::run(lambda_runtime::service_fn(|request| async {
                hello::handler(&common, request).await
            }))
            .await
        }
        "upload" => {
            lambda_runtime::run(lambda_runtime::service_fn(|request| async {
                upload::handler(&common, request).await
            }))
            .await
        }
        s => panic!("Missing handler for {s}"),
    }?;

    Ok(())
}