Using Ktor results in CallNotFoundException due to work on wrong thread

このレポートでは、withContext(Dispatchers.IO) 内で PlacesApi.placeAutocomplete(...).await() を再現しており、スタックトレースでは GaePendingResult.await を指しています。まず Ktor/App Engine リクエストを再現し、コルーチンディスパッチャーがライブラリのリクエスト処理とどのように相互作用するかを追跡してください。スレッド関連の失敗が確認され、リポジトリにサポート対象の修正または明確に文書化された互換性ガイダンスが存在すれば完了です。

I'm using Ktor, which is based on coroutines. This seems to be conflicting with the thread manager that the Google Maps Platform Java library uses. It keeps giving me an Unexpected exception from com.google.apphosting.api.ApiProxy$CallNotFoundException: Can't make API call urlfetch.Fetch in a thread that is neither the original request thread nor a thread created by ThreadManager error.

Environment details

1. Specify the API at the beginning of the title (for example, "Places: ...")
2. OS type and version
3. Library version and other environment information

Places Autocomplete
Kotlin 1.4
0.11.0

Steps to reproduce

1. Make a request to PlacesApi.placeAutocomplete(context, query, null).await()

Code example

fun Application.placesAutocomplete() {
    routing {
        get("/v1/places/autocomplete") {
            val parameters = call.request.queryParameters
            val query: String? = parameters["query"]
            val type: String? = parameters["type"]

            if (query == null) {
                call.respondParameterRequired("query")
                return@get
            }

            if (query.isBlank()) {
                call.respond(AutocompleteResponse(emptyList()))
                return@get
            }

            val PLACES_KEY = System.getenv("PLACES_KEY")

            val placeAutocompleteTypes = try {
                type?.let { PlaceAutocompleteType.valueOf(type) }
            } catch (e: IllegalArgumentException) {
                call.respond(HttpStatusCode.BadRequest, "Invalid place type")
                return@get
            }

            val context = GeoApiContext.Builder(GaeRequestHandler.Builder()).apiKey(PLACES_KEY).build()

            val placeAutocompleteRequest = PlacesApi.placeAutocomplete(context, query, null)
            placeAutocompleteTypes?.let { types ->
                placeAutocompleteRequest.types(types)
            }

            try {
                val placeAutocompleteResponse = withContext(Dispatchers.IO) { placeAutocompleteRequest.await() }
                val places = placeAutocompleteResponse.map {
                    val formatting = it.structuredFormatting
                    Place(
                        placeId = it.placeId, mainText = formatting.mainText
                            ?: "", secondaryText = formatting.secondaryText
                            ?: ""
                    )
                }

                val autocompleteResponse = AutocompleteResponse(places)
                call.respond(autocompleteResponse)
            } catch (e: Exception) {
                call.respond(HttpStatusCode.InternalServerError, e)
            }
        }
    }
}

Stack trace

com.google.maps.errors.UnknownErrorException: Unexpected exception from com.google.apphosting.api.ApiProxy$CallNotFoundException: Can't make API call urlfetch.Fetch in a thread that is neither the original request thread nor a thread created by ThreadManager
	at com.google.maps.internal.GaePendingResult.await(GaePendingResult.java:121)
	at com.google.maps.PendingResultBase.await(PendingResultBase.java:58)
	at appengine.PlacesAutocompleteKt$placesAutocomplete$1$1$placeAutocompleteResponse$1.invokeSuspend(PlacesAutocomplete.kt:74)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:56)
	at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:272)
	at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:79)
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:54)
	at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:36)
	at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
	at appengine.PlacesAutocompleteKt$placesAutocomplete$1$1.invokeSuspend(PlacesAutocomplete.kt:74)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTaskKt.resume(DispatchedTask.kt:175)
	at kotlinx.coroutines.DispatchedTaskKt.resumeUnconfined(DispatchedTask.kt:137)
	at kotlinx.coroutines.DispatchedTaskKt.dispatch(DispatchedTask.kt:108)
	at kotlinx.coroutines.CancellableContinuationImpl.dispatchResume(CancellableContinuationImpl.kt:307)
	at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl(CancellableContinuationImpl.kt:317)
	at kotlinx.coroutines.CancellableContinuationImpl.resumeWith(CancellableContinuationImpl.kt:249)
	at retrofit2.KotlinExtensions$awaitResponse$2$2.onResponse(KotlinExtensions.kt:93)
	at retrofit2.OkHttpCall$1.onResponse(OkHttpCall.java:129)
	at okhttp3.RealCall$AsyncCall.execute(RealCall.java:174)
	at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)