AWS Region provider that looks for the region in this order:
Check the 'aws.region' system property for the region.
Check the 'AWS_REGION' environment variable for the region.
Check the {user.home}/.aws/credentials and {user.home}/.aws/config files for the region.
If running in EC2, check the EC2 metadata service for the region.
Decorator metadata class for S3 to allow customers to opt in to using the
regional S3 us-east-1 endpoint instead of the legacy
s3.amazonaws.com when specifying the us-east-1 region.