OsmoMSC support for "Follow-on request/proceed"
TS 24.008 10.5.3.5 permits the MS to indicate that it has another transaction pending after the location update. This is done by means of the FOR bit in the LU Type IE. If this bit is set, and the MSC responds with "Follow on proceed" in the LOCATION UPDATE ACCEPT, a timer is started and the MS may proceed with sending a CM SERVICE REQUEST over the same radio connection.
We don't support this so far, but it would be a nice optimization.