Container for headers used in s3 uploads like acl, server side encryption, storage class, metadata or custom headers for more advanced use cases.
Documentation: http://docs.aws.amazon.com/AmazonS3/latest/dev/serv-side-encryption.html
Documentation: http://docs.aws.amazon.com/AmazonS3/latest/dev/storage-class-intro.html
Convenience apply methods for creation of canned acl, meta, encryption, storage class or custom headers.