### 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
appender.addExpectation(
                new MockLogAppender.PatternSeenEventExpectation(
                    "received request",
                    "org.elasticsearch.transport.TransportService.tracer",
                    Level.TRACE,
                    ".*\\[internal:test].*received request.*"
                )
            );
            
            appender.addExpectation(
                new MockLogAppender.PatternSeenEventExpectation(
                    "sent response",
                    "org.elasticsearch.transport.TransportService.tracer",
                    Level.TRACE,
                    ".*\\[internal:test].*sent response.*"
                )
            );
            
            appender.addExpectation(
                new MockLogAppender.PatternSeenEventExpectation(
                    "received response",
                    "org.elasticsearch.transport.TransportService.tracer",
                    Level.TRACE,
                    ".*\\[internal:test].*received response from.*\\{TS_B}.*"
                )
            );
            serviceA.sendRequest(nodeB, "internal:test", new StringMessageRequest("", 10), noopResponseHandler);
            assertBusy(appender::assertAllExpectationsMatched);