sourcestream: Do not process null streams
We have a callback that tells us that a stream has been destroyed and so we clean it up. Now we shouldn't process streams after this happened, otherwise we crash.
(cherry picked from commit b5266916)
We have a callback that tells us that a stream has been destroyed and so we clean it up. Now we shouldn't process streams after this happened, otherwise we crash.
(cherry picked from commit b5266916)