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kotlinlang

Let's start a thread on how to use Ktor `HttpClient` in a `Worker` (background thread) on native :slightly_smiling_face:

Workaround for <https://github.com/JetBrains/kotlin-native/issues/3061>
Use `TransferMode.UNSAFE` to move(!) the `HttpClient` instance to your `Worker`. Unless you create it directly within the worker in which case this is not necessary. In both cases it is stored in an `@ThreadLocal` variable.
```
worker.execute(TransferMode.UNSAFE, { HttpClient(Ios) }) { httpClient -&gt; threadLocalHttpClient = httpClient }
```

Launch the coroutine for executing `HttpClient` calls _inside_ your `Worker`.
```
GlobalScope.launch(Dispatchers.Unconfined) {
	// use HttpClient
}
```

Workaround for <https://github.com/Kotlin/kotlinx-io/issues/53>
```
body = TextContent(
	text = someJson,
	contentType = ContentType.Application.Json
)
```
-&gt;
```
body = ByteArrayContent(
	bytes = someJson.toUtf8(),
	contentType = ContentType.Application.Json
)
```

You cannot create a `HttpClient` instance on a non-main thread until this is fixed:
<https://github.com/ktorio/ktor/issues/1183>

There may be more of such issue though.

`NSURLSession` responds on the main thread and the coroutine continues on that thread due to `Unconfined` :disappointed:

Is there a better way of getting the coroutine execution back into the `Worker` rather than using `worker.execute(TransferMode.UNSAFE, …)`?

It looks like that problem can be solved by moving constants(and it fixed in the ios support branch). The next big problem is unfrozen values in `atomicfu` primitives and it can't be solved on ktor side for now.