Perform all necessary operations to unload file data from the object.
In the case where Efl.File.mmap.set has been externally called on an object, the file handle stored in the object will be preserved.
Calling Efl.File.unload on an object which is not currently loaded will have no effect.
Overridden from Efl.File.unload.
void efl_file_unload(Eo *obj);