Backport of "appsrc/appsink: Make setting/replacing callbacks thread-safe" into 1.16
requested to merge tpm/gst-plugins-base:backport-mr-570-into-1.16-app-callbacks-memory-management into 1.16
Backport of !570 (merged) "appsrc/appsink: Make setting/replacing callbacks thread-safe".
Commits:
- 9a55945c appsrc/appsink: Make setting/replacing callbacks thread-safe