### 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
public static final TransportInterceptor NOOP_TRANSPORT_INTERCEPTOR = new TransportInterceptor() {
    };
    
    private final Logger tracerLog;
    private final Tracer tracer;
    volatile String[] tracerLogInclude;
    volatile String[] tracerLogExclude;
    private final RemoteClusterService remoteClusterService;
    
    volatile DiscoveryNode localNode = null;
    private final Transport.Connection localNodeConnection = new Transport.Connection() {
        @Override
        public DiscoveryNode getNode() {
            return localNode;
        }
        @Override
        public void sendRequest(long requestId, String action, TransportRequest request, TransportRequestOptions options) {
            sendLocalRequest(requestId, action, request, options);
        }
        @Override
        public void addCloseListener(ActionListener<Void> listener) {}
        @Override
        public void addRemovedListener(ActionListener<Void> listener) {}
        @Override
        public boolean isClosed() {
            return false;
        }
        @Override
        public void close() {
            assert false : "should not close the local node connection";