@Override
  public MirrorType getMirrorType() {
    if (getDataPolicy().isNormal() || getDataPolicy().isPreloaded()
        || getDataPolicy().isEmpty() || getDataPolicy().withPartitioning()) {
      return MirrorType.NONE;
    } else if (getDataPolicy().withReplication()) {
      return MirrorType.KEYS_VALUES;
    } else {
      throw new IllegalStateException(
          String.format("No mirror type corresponds to data policy %s",
              getDataPolicy()));
    }
  }
Return a cache writer if this region has one. Note if region's writer is used to implement
bridge then null is returned.

@since GemFire 5.7
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractRegion.java