### Description

The `sendRequest` method is asynchronous and notifies a 
`TransportResponseHandler` when it completes the excecution
(successfully or unsuccessfully). 

When opening the connection we only catch `NodeNotConnectedException`
( https://github.com/elastic/elasticsearch/blob/main/server/src/main/java/org/elasticsearch/transport/TransportService.java#L719 ) which is currently fine as no implementations
throw other type of exception however, it'd be best to catch `Exception` here
so the `handler` gets notified of potential exceptions (as opposed to the caller
having to `try/catch` the call to `sendRequest`)
server/src/main/java/org/elasticsearch/cluster/coordination/PublicationTransportHandler.java
private final Map<Version, ReleasableBytesReference> serializedStates = new ConcurrentHashMap<>();
        private final Map<Version, ReleasableBytesReference> serializedDiffs = new HashMap<>();
        PublicationContext(ClusterStatePublicationEvent clusterStatePublicationEvent) {
            discoveryNodes = clusterStatePublicationEvent.getNewState().nodes();
            newState = clusterStatePublicationEvent.getNewState();
            previousState = clusterStatePublicationEvent.getOldState();
            task = clusterStatePublicationEvent.getTask();
            sendFullVersion = previousState.getBlocks().disableStatePersistence();
        }
        void buildDiffAndSerializeStates() {
            assert refCount() > 0;
            final LazyInitializable<Diff<ClusterState>, RuntimeException> diffSupplier = new LazyInitializable<>(
                () -> newState.diff(previousState)
            );
            for (DiscoveryNode node : discoveryNodes) {
                if (node.equals(transportService.getLocalNode())) {
                    
                    continue;
                }
                if (sendFullVersion || previousState.nodes().nodeExists(node) == false) {
                    serializedStates.computeIfAbsent(node.getVersion(), v -> serializeFullClusterState(newState, node));
                } else {
                    serializedDiffs.computeIfAbsent(
                        node.getVersion(),
                        v -> serializeDiffClusterState(newState.version(), diffSupplier.getOrCompute(), node)
                    );
                }
            }
        }
        public void sendPublishRequest(