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: s3-getting-started.rs
    path of file: ./repos/aws-sdk-rust/examples/examples/s3/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

#![allow(clippy::result_large_err)]

/*
Purpose

Shows how to use the AWS SDK for Rust to get started using
Amazon Simple Storage Service (Amazon S3). Create a bucket, move objects into and out of it,
and delete all resources at the end of the demo.


    
async fn initialize_variables() -> (Region, Client, String, String, String, String) {
    let region_provider = RegionProviderChain::first_try(Region::new("us-west-2"));
    let region = region_provider.region().await.unwrap();

    let shared_config = aws_config::from_env().region(region_provider).load().await;
    let client = Client::new(&shared_config);

    let bucket_name = format!("doc-example-bucket-{}", Uuid::new_v4());

    let file_name = "s3/testfile.txt".to_string();
    let key = "test file key name".to_string();
    let target_key = "target_key".to_string();

    (region, client, bucket_name, file_name, key, target_key)
}