DecodeMarkerV1 decodes the segment number from a segment marker, encoded with EncodeMarkerV1.

EncodeMarkerV1 encodes the segment number, from whom we need to create a marker, in the marker file format, which in v1 includes the segment number and a trailing CRC code of the first 10 bytes.

FindMarkableSegment finds, given the summary of data updates received, and a threshold on how much time can pass for a segment that hasn't received updates to be considered as "live", the segment that should be marked as last consumed.

NewMarkerFileHandler creates a new markerFileHandler.

NewMarkerHandler creates a new markerHandler.

MarkerFileHandler is a file-backed wal.Marker, that also allows one to write to the backing store as particular segment number as the last one marked.