IO::Buffer#or!

static VALUE
io_buffer_or_inplace(VALUE self, VALUE mask)
{
    struct rb_io_buffer_view *buffer = get_io_buffer_view_for_writing(self);

    struct rb_io_buffer_view *mask_buffer = get_io_buffer_view(mask);

    io_buffer_check_mask_size(mask_buffer->size);
    io_buffer_check_overlaps(buffer, mask_buffer);

    void *base;
    size_t size;
    io_buffer_get_bytes_for_writing(buffer, &base, &size);

    const void *mask_base;
    size_t mask_size;
    io_buffer_get_bytes_for_reading(mask_buffer, &mask_base, &mask_size);

    memory_or_inplace(base, size, (unsigned char *)mask_base, mask_size);

    return self;
}