NewDefaultWALFilter constructs an instance of DefaultWALFeeder.

DefaultWALFilter is a default implementation of WALFilter.

S3VersionFetcher is an implementation of VersionFetcher that uses an S3 client.

StorageState describes if an object is present on o storage and if so, in which version.

VersionFetcher fetches object's version.

WALFilter consults the storages to determine the desired state of an object.