void updateDiskRegion(AbstractDiskRegion diskRegion) {
    for (Oplog oplog : getAllOplogs()) {
      if (oplog != null) {
        oplog.updateDiskRegion(diskRegion);
      }
    }
  }
Returns null if we are not currently recovering the DiskRegion with the given drId.
geode-core/src/main/java/org/apache/geode/internal/cache/PersistentOplogSet.java