### 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/transport/TransportService.java
new ActionListenerResponseHandler<>(listener.delegateFailure((l, response) -> {
                if (clusterNamePredicate.test(response.clusterName) == false) {
                    l.onFailure(
                        new IllegalStateException(
                            "handshake with ["
                                + node
                                + "] failed: remote cluster name ["
                                + response.clusterName.value()
                                + "] does not match "
                                + clusterNamePredicate
                        )
                    );
                } else if (response.version.isCompatible(localNode.getVersion()) == false) {
                    l.onFailure(
                        new IllegalStateException(
                            "handshake with ["
                                + node
                                + "] failed: remote node version ["
                                + response.version
                                + "] is incompatible with local node version ["
                                + localNode.getVersion()
                                + "]"
                        )
                    );
                } else {
                    l.onResponse(response);
                }
            }), HandshakeResponse::new, ThreadPool.Names.GENERIC)
        );
    }