A function of this type is responsible for freeing the pixel array of a pixbuf. The Pixbuf.newFromData function lets you pass in a pre-allocated pixel array so that a pixbuf can be created from it; in this case you will need to pass in a function of GdkPixbufDestroyNotify so that the pixel data can be freed when the pixbuf is finalized.

alias GdkPixbufDestroyNotify = void function(char* pixels, void* data)