Using Ktor results in CallNotFoundException due to work on wrong thread

报告在 withContext(Dispatchers.IO) 中复现了 PlacesApi.placeAutocomplete(...).await()，并在堆栈跟踪中指向 GaePendingResult.await。首先复现 Ktor/App Engine 请求，并跟踪协程调度器如何与库的请求处理进行交互。确认与线程相关的故障，并且 repository 中有受支持的修复或明确记录的兼容性指导后，即可视为完成。

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)