public Bytes read_pixel_bytes ()
Provides a Bytes buffer containing the raw pixel data; the data must not be modified.
This function allows skipping the implicit copy that must be made if get_pixels is called on a read-only pixbuf.
A new reference to a read-only copy of the pixel data. Note that for mutable pixbufs, this function will incur a one-time copy of the pixel data for conversion into the returned Bytes.