Resolved Can't use async UnityWebRequest [CS1061]

I'm getting the following error when I use await request.SendWebRequest() inside a script that belongs to an Assembly Definition. I know that some assembly reference is missing but I can't find it. Without the Assembly Definition, everything works fine

error CS1061: 'UnityWebRequestAsyncOperation' does not contain a definition for 'GetAwaiter' and no accessible extension method 'GetAwaiter' accepting a first argument of type 'UnityWebRequestAsyncOperation' could be found (are you missing a using directive or an assembly reference?)

How to reproduce:

1. Create a default Assembly Definition, don't need to change anything
2. Create a script with this code
   
   Code (CSharp):

   1. using UnityEngine;
   2. using UnityEngine.Networking;
   3.  
   4. public class ScriptAbc : MonoBehaviour{
   5.  
   6.     public async void Anything() {
   7.         UnityWebRequest request = UnityWebRequest.Get("blabla");
   8.         await request.SendWebRequest();
   9.     }
   10.  
   11. }
   12.  

I'm using Unity 2020.3.33f1

 

Is it supposed to be awaitable?
You can yield it in a coroutine according to docs but it doesn‘t mention async/await support.

 

There is an assembly reference that makes it awaitable, I don't know which

 

Well just like the error message says

'UnityWebRequestAsyncOperation' does not contain a definition for 'GetAwaiter'

So it cannot be awaited as it doesn't have any definition to await.

There is an asset on the asset store that made extensions for it so it is awaitable.
https://assetstore.unity.com/packages/tools/integration/async-await-support-101056

But there's also UniTask at https://github.com/Cysharp/UniTask

 

The weird thing is that it works without the assembly definition

 

It ain't supported by default so you've got some other code somewhere that makes it possible like the 2 plugins I've linked.
If you'd create a new project, it shouldn't work either. If it does I'd be more surprised.

The code for awaiting

UnityWebRequestAsyncOperation

is somewhere in your project, it would need to be in its own assembly definition as well. Then anything else using it would need to reference this assembly definition. Which is why I never bother with assembly definitions. They always complicate things more than fixing anything.

 

You guys are right, it's not supported by default, it's an extension from a third-party package

Problem solved, thanks!!

 

what was the package?

adding this one to my asmdef helped https://github.com/RageAgainstThePixel/com.utilities.async

 

That's because that package contains the extensions to make it awaitable.

In 2023.1 and higher you can make use of the

Awaitable

API.
https://docs.unity3d.com/2023.1/Documentation/ScriptReference/Awaitable.html

Another option instead of awaiting is to use the

UnityWebRequestAsyncOperation.completed

event to handle whatever needs to be done.
https://docs.unity3d.com/2022.3/Documentation/ScriptReference/AsyncOperation-completed.html
That way you don't need a fire and forget

async void

method.