How do I ensure a streamed level finishes loading before I return control to the player?

I’m working on a basic fast travel system. Since my game is a seamless world that uses level streaming volumes to load/unload spaces, unless I’m missing something big fast travel is as simple as fading to black/to a cinematic to hide the transition, changing the player’s ACharacter location to the desired part of the world, then fading back in and returning control to the player.

However, I’m a little leery about trusting streaming to completely load and unload a level within the blink of an eye- after I fade to black and teleport the character into the new streaming volume, is there any way to be 110% sure that the new area has finished loading before I return control to the player?