AWS S3 区域标识符，也可以传入自定义值，在这种情况下，您需要传递一个有效的端点，否则会发生错误 :)

示例

use std::str::FromStr;
use awsregion::Region;

// Parse from a string
let region: Region = "us-east-1".parse().unwrap();
// Choose region directly
let region = Region::EuWest2;

// Custom region requires valid region name and endpoint
let region_name = "nl-ams".to_string();
let endpoint = "https://s3.nl-ams.scw.cloud".to_string();
let region = Region::Custom { region: region_name, endpoint };