def gen_marker(size_in_bytes):
    """
    Returns a pattern of the given size.
    We need a marker with distinct bytes to avoid overlaps
    with instructions that begin with the same byte as the marker.
    """
    marker = ''
    for i in range(0, size_in_bytes):
        marker = f'{marker}{i+1:02x}'
    return int(marker, 16)