in src/main/java/com/spotify/futures/CombinedFutures.java [42:52]
public <T> T get(CompletionStage<T> stage) {
final Object value = map.get(stage);
if (value == null) {
throw new IllegalArgumentException(
"Can not resolve values for futures that were not part of the combine");
}
if (value == NULL_PLACEHOLDER) {
return null;
}
return (T) value;
}