How would an application operate an appsink in pull mode?

[Patrick Doyle]

I was just reading the documentation for the appsink API
(http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-appsink.html)
and read in the section for gst_app_sink_set_emit_signals() that "This
option is by default disabled because signal emission is expensive and
unneeded when the application prefers to operate in pull mode."

After reading that, I started wondering, how an application would
operate an appsink in pull mode?  Given my very limited exposure to
the internals Gstreamer applications (I have only ever seen the
example code in the documentation), it seems to me that a Gstreamer
application just runs g_main_loop() and let's the event handlers do
all of the work.  That doesn't seem compatible with the
gst_app_sink_pull_sample() function which would block the event
handler.

Thank you for any light you care to shed on this topic.

--wpd