@Override
  public IndexInput openInput(String name, IOContext context) throws IOException {
    ensureOpen();
    final File file = fs.getFile(name);
    return new FileIndexInput(name, file);
  }
Create a region directory with a given file and chunk region. These regions may be bucket
regions or they may be replicated regions.
geode-lucene/src/main/java/org/apache/geode/cache/lucene/internal/directory/RegionDirectory.java