No EOS message when filesrc is connected to webrtcbin

[Anthony Alba]

Problem: when I connect a filesrc to a webrtcbin (to send pre-encoded
data) I don't see the EOS message on the bus, so I am not able to
close the pipeline gracefully.

Is this to be expected? The pipeline is

webrtcbin name=sendonly stun-server=stun://stun.l.google.com:19302

filesrc location=INPUTFILE ! matroskademux name=demux

demux.audio_0 ! rtpopuspay !
 queue ! application/x-rtp,media=audio,encoding-name=OPUS,payload=96 ! sendonly.

demux.video_0 ! rtpvp8pay !
 queue ! application/x-rtp,media=video,encoding-name=VP8,payload=97 ! sendonly.

INPUTFILE is .mkv with known streams, i.e., 1 x OPUS audio stream and
1 x VP8 video stream. I do not want to incur the overhead of
reencoding.

If I use a urldecodebin, and incur the overhead of reencoding, I can
handle the drained signal, and shutdown the pipeline.

In this case, how would you detect that the filesrc is finished?

Anthony