This function allows code to run ao2_ref against the real
object associated with a weakproxy. It is useful when
all of the following conditions are true:
* You have a pointer to weakproxy.
* You do not have or need a pointer to the real object.
* You need to ensure the real object exists and is not
destroyed during a process.
In this case it's wasteful to store a pointer to the real
object just for the sake of releasing it later.
Change-Id: I38a319b83314de75be74207a8771aab269bcca46
This implements "weak" references. The weakproxy object is a real ao2 with
normal reference counting of its own. When a weakproxy is pointed to a normal
object they hold references to each other. The normal object is automatically
freed when a single reference remains (the weakproxy). The weakproxy also
supports subscriptions that will notify callbacks when it does not point
to any real object.
ASTERISK-24936 #close
Reported by: Corey Farrell
Change-Id: Ib9f73c02262488d314d9d9d62f58165b9ec43c67
Corey Farrell