97e748466e
Test included. The problem appears when aggregator drops the query while it's being proccessed by the klass->sink_query handler. This can happen on FLUSH_START event. If the query is still in the queue, it can be safely dropped, but if it's already in the klass->sink_query() handler, then sink pad has no choice and has to wait for the proccessing to complete. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5765>