### 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 void handleResponse(Version1Response response) {
                    assertThat(response.value1, equalTo(1));
                    assertThat(response.value2, equalTo(0)); 
                }
                @Override
                public void handleException(TransportException exp) {
                    logger.error("Unexpected failure", exp);
                    fail("got exception instead of a response: " + exp.getMessage());
                }
            }
        ).get();
        assertThat(version1Response.value1, equalTo(1));
        assertThat(version1Response.value2, equalTo(0));
    }
    public void testVersionFrom1to1() throws Exception {
        serviceB.registerRequestHandler("internal:version", ThreadPool.Names.SAME, Version1Request::new, (request, channel, task) -> {
            assertThat(request.value1, equalTo(1));
            assertThat(request.value2, equalTo(2));
            Version1Response response = new Version1Response(1, 2);
            channel.sendResponse(response);
            assertEquals(version1, channel.getVersion());
        });
        Version1Request version1Request = new Version1Request();
        version1Request.value1 = 1;
        version1Request.value2 = 2;
        Version1Response version1Response = submitRequest(
            serviceB,
            nodeB,
            "internal:version",