Hi, I'm trying to use VipsSourceCustom to support streaming in a generic way for the language binding I'm trying to create.

I could not find details about premature termination of read. For example if I'm making web request for every read, and I face a network issue how to stop it gracefully? ie. what should be the return value?

Also, if I'm writing the output to a file, and the operation stopped abruptly, the output file is left in the fs(with size zero). Ideally it should be deleted?

fwiw, I tried returning -1 for the very first read, and that lead to segfault when I attempted vips_image_new_from_source for that source.