-/** A copy/snapshot of a given memory region
- *
- * Different types of region snapshot storage types exist:
- *
- * * flat/dense snapshots are a simple copy of the region;
- *
- * * sparse/per-page snapshots are snaapshots which shared
- * identical pages.
- *
- * * privatized (SMPI global variable privatization).
- *
- * This is handled with a variant based approach:
- *
- * * `storage_type` identified the type of storage;
- *
- * * an anonymous enum is used to distinguish the relevant types for
- * each type.
- */