private string GetReprToString() {
var code = Invariant($"rtvs:::repr_toString(eval(quote({EvaluationResult.Expression}), envir = {EvaluationResult.EnvironmentExpression}))");
return TaskExtensions.RunSynchronouslyOnUIThread(ct => StackFrame.Engine.Tracer.Session.EvaluateAsync<string>(code, REvaluationKind.Normal, ct));
}