### 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 TransportStats stats() {
        return transport.getStats();
    }
    public boolean isTransportSecure() {
        return transport.isSecure();
    }
    public BoundTransportAddress boundAddress() {
        return transport.boundAddress();
    }
    public List<String> getDefaultSeedAddresses() {
        return transport.getDefaultSeedAddresses();
    }
    /**
     * Returns <code>true</code> iff the given node is already connected.
     */
    public boolean nodeConnected(DiscoveryNode node) {
        return isLocalNode(node) || connectionManager.nodeConnected(node);
    }
    /**
     * Connect to the specified node with the given connection profile.
     * The ActionListener will be called on the calling thread or the generic thread pool.
     *
     * @param node the node to connect to
     * @param listener the action listener to notify
     */
    public void connectToNode(DiscoveryNode node, ActionListener<Releasable> listener) throws ConnectTransportException {
        connectToNode(node, null, listener);
    }
    /**