### 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`)
test/framework/src/main/java/org/elasticsearch/transport/AbstractSimpleTransportTestCase.java
}
            }
            @Override
            public String executor() {
                return randomFrom(executors);
            }
        };
        ConnectionProfile.Builder builder = new ConnectionProfile.Builder();
        builder.addConnections(
            1,
            TransportRequestOptions.Type.BULK,
            TransportRequestOptions.Type.PING,
            TransportRequestOptions.Type.RECOVERY,
            TransportRequestOptions.Type.REG,
            TransportRequestOptions.Type.STATE
        );
        try (Transport.Connection connection = openConnection(serviceB, serviceC.getLocalNode(), builder.build())) {
            serviceC.close();
            serviceB.sendRequest(
                connection,
                "internal:action",
                new TestRequest("boom"),
                TransportRequestOptions.EMPTY,
                transportResponseHandler
            );
        }
        latch.await();
    }
    public void testConcurrentDisconnectOnNonPublishedConnection() throws IOException, InterruptedException {
        MockTransportService serviceC = buildService("TS_C", version0, Settings.EMPTY);