Completion Exception

## What happened

(please describe what you were doing when this exception occurred)

## Version information

IntelliJ IDEA `2020.2.4` • Flutter plugin `io.flutter 52.0.4` • Dart plugin `202.8070`

Error getting Flutter sdk information.

## Exception

null

```
java.util.concurrent.CompletionException: java.lang.RuntimeException: RPCError calling getObject: org.dartlang.vm.service.element.RPCError@61ec2981
at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:331)
at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:346)
at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:632)
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
at java.base/java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:2088)
at io.flutter.inspector.EvalOnDartLibrary.lambda$addRequest$0(EvalOnDartLibrary.java:97)
at java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:859)
at java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:837)
at java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:479)
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)
Caused by: java.lang.RuntimeException: RPCError calling getObject: org.dartlang.vm.service.element.RPCError@61ec2981
at io.flutter.inspector.EvalOnDartLibrary$3.onError(EvalOnDartLibrary.java:226)
at org.dartlang.vm.service.VmServiceBase.processResponse(VmServiceBase.java:629)
at org.dartlang.vm.service.VmServiceBase.processMessage(VmServiceBase.java:422)
at org.dartlang.vm.service.VmServiceBase$1.onMessage(VmServiceBase.java:86)
at de.roderick.weberknecht.WebSocketReceiver.run(WebSocketReceiver.java:65)
```

Start with the stack trace in io.flutter.inspector.EvalOnDartLibrary.java, especially the getObject request, and follow the error through VmServiceBase.java. Use the reported IntelliJ IDEA, Flutter plugin, and Dart plugin versions to investigate the RPCError; done means the exception is reproducibly diagnosed and the Flutter SDK information request no longer fails.

Written by the indexing model from the issue text.