BytesStreamOutput out = new BytesStreamOutput();
int position = 0;
assertEquals(position, out.position());
out.seek(position += 10);
out.seek(position += BigArrays.BYTE_PAGE_SIZE);
out.seek(position += BigArrays.BYTE_PAGE_SIZE + 10);
out.seek(position += BigArrays.BYTE_PAGE_SIZE * 2);
assertEquals(position, out.position());
assertEquals(position, out.bytes().toBytes().length);