Any beginning literal portion of a filter expression is used to generate a search prefix which often helps keep the request small enough to avoid rate limiting.
Suggested by Mihail Shvein.
Refactor storage layer to allow for new repository filesystems using drivers. (Reviewed by Cynthia Shang.)
Refactor IO layer to allow for new compression formats, checksum types, and other capabilities using filters. (Reviewed by Cynthia Shang.)
