Tombstones

There may be cases where an entity which was contained within a FIRES dataset becomes permanently unavailable, in these situations, rather than everyone retaining the data previously published, we can publish a Tombstone record.

A tombstone change record signals to consumers that they can permanently remove all the FIRES data about that entity. This allows for databases to be cleaned up when data is no longer relevant, and also allows for compaction of the FIRES dataset, if necessary.