[Discuss-gnuradio] Carrier Sensing only in gr_packet_sink?

[Marius]

Hi!

I have a short question: in my implementation of a state machine to
implement a parser for a MAC sublayer standard (802.15.4) I used a
Sync-Block. Now I found out that carrier_sense() is only in
gr_packet_sink class. Does this make sense at all? Normally I'd apply
some Carrier Sensing right before modulation, mostly to avoid blocks
wasting performance on iterating over noise. I'm aware that a Squelch
Filter might archive a similar effect, but that still means the other
Signal Block go into general_work() routines.
So, why is carrier_sense() not in gr_sync_block etc.?

Best,
Marius