startSteeredSsaiSession
open suspend fun startSteeredSsaiSession(vendor: StitchedStreamVendor, assetParameters: Map<String, String>?): String
Open a full-service IMA DAI session for the manifest-steered ssai stream vendor describes and return the stitched stream URL to play on the CONTENT player (ADS-326). Suspends until IMA returns the URL.
Distinct from startGamSession, which opens a pod-serving session for ads the SDK stitches and plays itself: here the ads are already in the stream.
The default throws, so a renderer without an IMA DAI integration reports the gap through DA-SSAI-SESSION-FAILED instead of appearing to steer into ssai.