Starting a new thread just for dealing with AWS regions better, context S3
S3FileSystem.amazonS3 build could be refactored to select region based on
1. the flag value region
2. the EC2 region, if found in environment (running in EC2 VM)
3. the default region (us-east-1)
For actually moving data, a Map<String, AmazonS3> could be used to hold an
S3 client per region, new S3 clients created as needed. The "master" client
can be used to find a bucket's region .
I think this is pragmatic, looking for feedback before I write a PR. Also,
if someone is already making progress, let me know.