*
* @return The row key for writing to the state table if successfully claimed or {@code null} if not claimed.
*/
private byte[] claimEntry(StreamFileOffset offset, byte[] claimedStateContent) throws IOException {
ByteArrayDataOutput out = ByteStreams.newDataOutput(50);
out.writeLong(consumerConfig.getGroupId());
StreamUtils.encodeOffset(out, offset);
byte[] row = out.toByteArray();
SortedMap<byte[], byte[]> rowStates = getInitRowStates(row);