private HRegion createHRegion(TableDescriptor td, RegionInfo info, String dir, WAL wal,
    Durability durability) throws IOException {
    Path path = new Path(DIR, dir);
    if (FS.exists(path)) {
      if (!FS.delete(path, true)) {
        throw new IOException("Failed delete of " + path);
      }
    }
    ChunkCreator.initialize(MemStoreLAB.CHUNK_SIZE_DEFAULT, false, 0, 0, 0, null,
      MemStoreLAB.INDEX_CHUNK_SIZE_PERCENTAGE_DEFAULT);
    return HRegion.createHRegion(info, path, CONF, td, wal);
  }
Test when returnResults set to false in increment it should not return the result instead it
resturn null.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestDurability.java