### 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
randomFrom(ThreadPool.Names.SAME, ThreadPool.Names.GENERIC),
                TestRequest::new,
                (request, message, task) -> { throw new AssertionError("boom"); }
            )
        );
        serviceA.registerRequestHandler(
            "internal:action1",
            randomFrom(ThreadPool.Names.SAME, ThreadPool.Names.GENERIC),
            TestRequest::new,
            (request, message, task) -> { throw new AssertionError("boom"); }
        );
    }
    public void testTimeoutPerConnection() throws IOException {
        assumeTrue("Works only on BSD network stacks", Constants.MAC_OS_X || Constants.FREE_BSD);
        try (ServerSocket socket = new MockServerSocket()) {
            
            
            
            
            
            socket.bind(getLocalEphemeral(), 1);
            socket.setReuseAddress(true);
            DiscoveryNode first = new DiscoveryNode(
                "TEST",
                new TransportAddress(socket.getInetAddress(), socket.getLocalPort()),
                emptyMap(),
                emptySet(),
                version0
            );
            DiscoveryNode second = new DiscoveryNode(