How to throw error correctly in actor method?

I have an actor within following method
```go
func (t *TestActor) Invoke(ctx context.Context, req string) (string, error) {
return "", errors.New("Custom Message")
}
```
And I invoke the actor like this
```go
ctx, _ = context.WithTimeout(ctx, time.Second*15)
rsp, err := myActor.Invoke(ctx, "laurence")
if err != nil {
panic(err)
}
fmt.Println("get invoke result = ", rsp)
```
It should always go `panic(err)`, but the error shown is always "panic: error invoking binding testActorType/ActorImplID5121f5e3-bb26-4362-a199-e20ec9ebd5d5: rpc error: code = Internal desc = error invoke actor method: rpc error: code = Internal desc = error invoke actor method: error from actor service: "

Please advise..., also how to customize the grpc error code? now its always "Internal".

Start with TestActor.Invoke and the myActor.Invoke call shown in the issue, then trace how the actor RPC error is propagated and mapped to gRPC status codes. Confirm whether the custom message and status code are preserved or lost; done means documenting the supported behavior or identifying a reproducible SDK change needed to preserve or customize them.

Written by the indexing model from the issue text.