questions about gr-osmosdr

Hello, I'm working on the gr-osmosdr blocks for the Red Pitaya SDR transceiver. They are based on the file block with some pieces borrowed from the rtl_tcp block. The new blocks are already working and the code can be found at: https://github.com/pavel-demin/gr-osmosdr/tree/master/lib/red_pitaya My notes about the Red Pitaya SDR transceiver can be found at: http://pavel-demin.github.io/red-pitaya-notes/sdr-transceiver I have two questions that I can't find an answer to: - What would be the best way to implement the push-to-talk (PTT) command? I don't see any method reserved for this kind of functionality in gr-osmosdr/lib/sink_impl.h. I can think of putting it to set_if_gain or set_bb_gain but I'm not sure if it's a good idea. - Once the PTT problem solved, what would be the best way to submit a patch with my modifications? Best regards, Pavel