Best way to call async from non-async function and use delegate on complete

[andypoly]

(Runtime use) I see that all non async use has been deprecated which makes sense, however... it is interesting that this API uses Task which I have not personally seen used anywhere else in Unity code or packages. There is a big hole in my C# knowledge around Tasks (hopefully the only hole!). All the examples tend to use a new monobehaviour with an async Start() method or just start from an async call but consider examples starting from a non-async method and what if you want a delegate on completion of loading say?

[atteneder]

I get that a new concept like async can be intimidating at first.

However, the import/export processes of glTFast are inherently async and using it makes a lot of sense (both from performance and maintainability).

I followed the Microsoft Framework Design Guidelines and do not offer sync variants of any API method.

One can invoke a glTFast process from a sync context in a fire-and-forget. However, that has implications on how error handling has to happen and, as you figured, awaiting the result becomes harder.

I recommend all devs to invest the time and invoke glTFast methods from async methods only.

hth

[andypoly]

I get this and a Unity bug did not help my adoption of async by throwing errors with "thread" in!! But... how can you not start off a glTFast process from a sync context if at some point in your app you need to import a model and basically all your other code is non-async? Unless you can have an async Update to trigger the calls I don't see the way as your example for runtime is in async Start, like at app/scene startup, it does do via some 'request'

[atteneder]

I'm afraid I still don't get your problem. Can you provide an example?

I'd recommend you read about Async, tasks and Awaitable. Async code in Unity (and that includes glTFast) assumes the use of the UnitySynchronizationContext, which ensures awaited Tasks are continued on the main thread and that matches my observation. Please show me where your observation deviates from that.

[andypoly]

It is a change of thinking which some people are having trouble with using async in Unity.
Normally in Unity you do fire and forget with StartCoroutine for something like this at runtime (loading data etc.), so you can continue in some update/frame/current-function code and not wait for anything.
So it is just about the best way to do that in Unity if a call is async not a coroutine, i.e:

void Update()
{
  //do some game/app logic
  //detect something has triggered a need to load a glb model!!
  //start off coroutine to load it (but it is async so call an async void function that awaits a Task?)
  //finish update logic for game/app
}

async void LoadBinaryModel(...)
{
  bool success = await import.LoadGltfBinary(...)
  //send a mesage/delegate etc.
}