ref_sink
Description:
public Object ref_sink ()
Increase the reference count of object, and possibly remove the floating reference, if object
has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by
clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal
reference increasing the reference count by one.
Returns:
