Major Description
The class org.apache.cxf.jaxrs.sse.SseBroadcasterImpl does not uphold the contract stated in javax.ws.rs.sse.SseBroadcaster interface.
The registered onError and onClose callbacks are not called when SseEventSink is closed or there is an communication error/timeout.
It seems the problem can be pinpointed to anonymous implementation of AsyncListener registered in AsyncContext from SseBroadcasterImpl.register method (GitHub link HERE).
Seems like extending the onComplete and onTimeout/onError methods to do additional calls to closers.forEach and exceptioners.forEach might solve this.