Saves pixbuf to an output stream.
Supported file formats are currently "jpeg", "tiff", "png", "ico" or "bmp". See Pixbuf.saveToStream for more details.
a gio.OutputStream to save the pixbuf to
name of file format
name of options to set, NULL-terminated
values for named options
optional gio.Cancellable object, NULL to ignore
TRUE if the pixbuf was saved successfully, FALSE if an error was set.
GException on failure.