How to measure interlatency for two piplines joined by shmsink --> shmsrc

[MTDziCOCO]

I have two pipelines, the first one:

GST_TRACERS="interlatency" GST_DEBUG=GST_TRACER:7 gst-launch-1.0 \
    videotestsrc ! \
    'video/x-raw,width=300,height=300,format=(string)I420,framerate=(fraction)10/1' ! \
    videoconvert ! \
    shmsink socket-path=/tmp/foo shm-size=20000000 wait-for-connection=0

yields the following output:

...
0:00:09.090158261 13199   0x5576daa400 TRACE             GST_TRACER :0:: interlatency, from_pad=(string)videotestsrc0_src, to_pad=(string)shmsink0_sink, time=(string)0:00:00.000523762;
...

Awesome!

The second pipeline:

GST_TRACERS="interlatency" GST_DEBUG=GST_TRACER:7 gst-launch-1.0 \
    shmsrc socket-path=/tmp/foo ! \
    'video/x-raw, width=300,height=300, format=(string)I420, framerate=(fraction)10/1' ! \
    videoconvert ! \
    appsink

yields the following:

...
0:00:02.387404889 13400   0x5595e28f20 TRACE             GST_TRACER :0:: interlatency, from_pad=(string)shmsrc0_src, to_pad=(string)appsink0_sink, time=(string)0:00:00.001616600;
...

Again -- very awesome!

But how can I measure the interlatency between shmsink and shmsrc?