code: Delta newDropFacade(Storage facade) {
          Delta storageDelta = Deltas.mapBuilder()
                  .put(StorageState.DROPPED.getMarkerAttribute().key(), now())
                  .build();
  
          MapDeltaBuilder storageMapDelta = Deltas.mapBuilder();
          for (Storage storage : facade.getPrimaryAndMirrors()) {
              storageMapDelta.update(storage.getUuidString(), storageDelta);
          }
  
          return Deltas.mapBuilder()
                  .update(STORAGE.key(), storageMapDelta.build())
                  .build();
      }
docs: Mark a facade as dropped.  A maintenance job will come along later and actually purge the data.