Is your feature request related to a problem? Please describe.
When using NetworkingSceneManager, the old scene gets unloaded after the new scene finsihed loading. Thus, the start methods of the new scene might cache the wrong refrences (main.Camera for example) on the old scene jsut before it gets unloaded.
Currently you have take care and make sure that you don't accidently cache obejcts from the old scene

Describe the solution you'd like
A way of being sure that the old scene is unloaded, before the new start methods fire.
to quote "Petter" here for a possible solution:

"It would maybe be possible to first load a temporary scene[,] copy the networkedobjects over to the temporary scene[,] unload the old scene[,] load the new scene and copy them over from the temporary scene to the new scene.

The temporary scene could maybe be the dont destroy on load scene."

This would make it much more intuitive to use the NetworkingSceneManager.