A modern programming language that makes developers happier.

kotlinlang

A colleague has this error in his *runtime* logs, but *inconsistently*, and the same code runs consistently fine on every other environment:
```
Caused by: java.lang.ClassCastException: class org.apache.pulsar.client.impl.BatchMessageIdImpl cannot be cast to class kotlin.Unit (org.apache.pulsar.client.impl.BatchMessageIdImpl and kotlin.Unit are in unnamed module of loader 'app')
    at app.SomeConsumer$invoke$1.invokeSuspend(SomeConsumer.kt:40) ~[classes/:?]
    ... suppressed 5 lines
```
The line at `SomeConsumer:40` is a suspending lambda that invokes a suspend function which returns nothing i.e. `Unit`. The last line of that suspend function is actually a `CompletableFuture.await()` suspending call that produces an `org.apache.pulsar.client.impl.BatchMessageIdImpl`, but the function is defined to return Unit (and even if the last line of the function is changed to `Unit` this still happens. Weird!