static ItIt<byte[]> byteArrayChunksIterator(byte[] l, int chunkSize) {
  ret iteratorFromFunction(new IF0<byte[]>() {
    int n = l(l), i;
    
    public byte[] get() {
      if (i >= n) null;
      i += chunkSize;
      ret subByteArray(l, i-chunkSize, i);
    }
  });
}

Began life as a copy of #1026949