Editor.AsyncStaticMeshPlayInEditorMode

0 - Wait until all static meshes are built before entering PIE. (Slowest but causes no visual or behavior artifacts.)1 - Wait until all static meshes affecting navigation and physics are built before entering PIE. (Some visuals might be missing during compilation.2 - Wait only on static meshes affecting navigation and physics when they are close to the player. (Fastest while still preventing falling through the floor and going through objects.