### 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
connectionManager.disconnectFromNode(node);
    }
    public void addMessageListener(TransportMessageListener listener) {
        messageListener.listeners.add(listener);
    }
    public boolean removeMessageListener(TransportMessageListener listener) {
        return messageListener.listeners.remove(listener);
    }
    public void addConnectionListener(TransportConnectionListener listener) {
        connectionManager.addListener(listener);
    }
    public void removeConnectionListener(TransportConnectionListener listener) {
        connectionManager.removeListener(listener);
    }
    public <T extends TransportResponse> void sendRequest(
        final DiscoveryNode node,
        final String action,
        final TransportRequest request,
        final TransportResponseHandler<T> handler
    ) {
        sendRequest(node, action, request, TransportRequestOptions.EMPTY, handler);
    }
    public final <T extends TransportResponse> void sendRequest(
        final DiscoveryNode node,
        final String action,
        final TransportRequest request,
        final TransportRequestOptions options,
        TransportResponseHandler<T> handler
    ) {
        final Transport.Connection connection;