SceneLoader.ImportMeshAsync "hangs" until the display is tapped

[ryantrem]

When calling SceneLoader.ImportMeshAsync, it "hangs" (does not complete) until the screen is tapped. You can tap anywhere, even on a different UI element (like a React Native button) and suddenly the function completes and the app runs. This repros on both Android and iOS.

[ryantrem]

I did some more testing and it seems like we can get stuck on one of several (any?) calls into Babylon Native that end up in native code (until you tap the display, then things get unstuck). The behavior is very similar on both Android and iOS. Need more digging and debugging.

[ryantrem]

Getting a bit more clarity on this... it seems like with "slow" async functions, the looper goes to sleep, and is woken up to call resolve, but resolve does not synchronously run the js continuations (thens). Somehow those get queued, but the looper is not worken up so they just sit in the queue until something wakes up the looper (e.g. user input, looper based timers, etc.). I need to understand better how promises work under the hood, particularly in the context of a JS engine like JavaScriptCore that does not manage its own threads or work queues but rather expects the caller to do this.