RTP marker events overwritten by follow on events

[liudude123]

RTP event messages write to the same jitter buffer frame. so follow on events overwrite the marker events.
The result is that mpf_dtmf_detector_get_frame() will discard the event frame as it would not have the marker flag set.
The reason for the overwrite is that in mpf_jitter_buffer_event_write() subsequent update events with different duration from the marker event (code attached below):
/* an update */ if(named_event->duration < jb->event_write_update->duration) { /* ignore this update, it's something from the past, which makes no sense now */ return JB_OK; } else if(named_event->duration == jb->event_write_update->duration) {
This allows the update frame to overwrite the marker frame.
Wireshark trace of such a call is attached
wscap_20180821_01_dtmf1234567890.zip