Hi,
in the
notifyNewSession and
notifyUser methods of the MetadataProvider you can inspect the http headers of the create_session request, you can log it from there; is this enough for your goals? (obviously you have to code your own metadata adapter to log that information)
Otherwise you can set the LightstreamerLogger.connections.http log category to DEBUG level, this will log all the request/response details: it may be not feasible to use this option if you have a high load on the server
HTH