@SuppressWarnings("UnsafeFinalization")
  public void writeIdInBytes(byte[] dest, int offset) throws IOException {
    System.arraycopy(idInBytes, 0, dest, offset, ID_SIZE);
  }
Writes id bytes to the given array starting from offset.
@param dest   output array
@param offset starting offset of the output array
hbase-common/src/main/java/org/apache/hadoop/hbase/io/encoding/DataBlockEncoding.java