Incomplete st30p Rx/Tx session statistics

[DianaEs2]

There are useful functions in MTL to get session's statistics. They work for st20p video but not for st30p audio or st40 ancillary.
Video statistics works well for st20p_rx_get_session_stats, st20p_tx_get_session_stats
But audio stats does not work. For example, st30p_rx_get_session_stats.

Here is my config for RxTxApp local_tx_rx_1a.json

I made a small code change to see the result of st30p_rx_get_session_stats commit-922bee7.patch

app_rx_st30p_stat does not show bitrate (stats.common.port[port].bytes = 0)
app_dump_io_stat(0), tx 2.737218 Mb/s rx 0.000000 Mb/s
app_dump_io_stat(1), tx 2.737218 Mb/s rx 0.000000 Mb/s
app_dump_io_stat(2), tx 0.000000 Mb/s rx 2.705475 Mb/s
app_dump_io_stat(3), tx 0.000048 Mb/s rx 2.704933 Mb/s
app_rx_st30p_stat(0,0), rx 0.000000 Mb/s fps 93.399693
app_rx_st30p_stat(0,1), rx 0.000000 Mb/s fps 6.599978