initAdsLoader
Creates the shared native IMA loader (wrapped by QPIMAAdsLoader) if it does not exist and, if adRequest is provided and no prefetch slot exists yet, immediately starts prefetching it via a fresh QPPrefetchAdsManager. An existing slot is kept as is; call deinitAdsLoader first to replace it.
Parameters
context
Any android.content.Context; the application context is used internally to avoid leaks.
playerView
The view used by the dedicated prefetch player to render the Pre-Roll.
adRequest
The Pre-Roll ad request to prefetch. Uses our SDK's existing AdRequest model.