The image loader is responsible for storing the given function pointers
and user data, and call them when needed.
The image loader should set up an internal state object, and return it
from this function; the state object will then be updated from the
[callback@GdkPixbuf.PixbufModuleIncrementLoadFunc] callback, and will be freed
by [callback@GdkPixbuf.PixbufModuleStopLoadFunc] callback.
the data to be passed to
[callback@GdkPixbuf.PixbufModuleIncrementLoadFunc]
and [callback@GdkPixbuf.PixbufModuleStopLoadFunc], or NULL in case of error
Sets up the image loading state.
The image loader is responsible for storing the given function pointers and user data, and call them when needed.
The image loader should set up an internal state object, and return it from this function; the state object will then be updated from the [callback@GdkPixbuf.PixbufModuleIncrementLoadFunc] callback, and will be freed by [callback@GdkPixbuf.PixbufModuleStopLoadFunc] callback.