def write_zeros(fileobj, count, block_size=8194):
    """ Write `count` zero bytes to `fileobj`

    Parameters
    ----------
    fileobj : file-like object
        with ``write`` method
    count : int
        number of bytes to write
    block_size : int, optional
        largest continuous block to write.
    """
    nblocks = int(count // block_size)
    rem = count % block_size
    blk = b'\x00' * block_size
    for bno in range(nblocks):
        fileobj.write(blk)
    fileobj.write(b'\x00' * rem)
