UniAndGroup never completes for empty list of unis.

[lordvlad]

This code will never complete.

Uni.combine().all().unis(List.of()).subscribe(x -> System.out.println("yay"));

The unis method should have a guard to fire an event when the list of inputs is empty. Otherwise one always needs to guard the code beforehand like.

var combined = unis.isEmpty() ? Uni.createFrom().voidItem() : Uni.combine().all().unis(unis);

[jponge]

We should perhaps enforce the contract specified in the Javadoc:

@param unis the list of unis, must not be {@code null}, must not contain {@code null}, must not be empty

This is not enforced and should be.