/**
* @return the first key in the file. May be null if file has no entries. Note that this is not
* the first row key, but rather the byte form of the first KeyValue.
*/
@Override
public byte[] getFirstKey() {
if (dataBlockIndexReader == null) {
throw new BlockIndexNotLoadedException();
}
return dataBlockIndexReader.isEmpty() ? null : dataBlockIndexReader.getRootBlockKey(0);
}
