public static void writeByteArray(final DataOutput out,final byte[] b,final int offset,final int length) throws IOException {
  WritableUtils.writeVInt(out,length);
  out.write(b,offset,length);
}

public static void writeByteArray ( final DataOutput out , final byte [ ] b , final int offset , final int length ) throws IOException { WritableUtils . writeVInt ( out , length ) ; out . write ( b , offset , length ) ; }
write byte - array to out with a vint length prefix .
