public interface QueueItemProvider<Q>
extends java.util.Iterator<java.util.Collection<Q>>, java.lang.Iterable<java.util.Collection<Q>>
MessageProviderjava.util.Iterator<java.util.Collection<Q>> iterator()
this. QueueItemProviders are not generally reusable/resettable since the
underlying message source will often not be reversible. Mashing the two interfaces together simplifies
implementations a bit, and also supports any typical Iterable usage.iterator in interface java.lang.Iterable<java.util.Collection<Q>>