NewMemChecksumMapper instantiates a new ChecksumMapper.

NewMultiBucketClient creates an s3 wrapped client that lists buckets as top level folders.

MaxCopyObjectSize is 5GB => if greater, we have to switch to multipart.

Client wraps a Minio Client to speak with an S3-compatible backend.

MemChecksumMapper is an in-memory implementation for ChecksumMapper interface.

ChecksumMapper maintains a mapping of eTags => checksum.