### 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
includeSettings = randomBoolean() ? "*" : "";
            excludeSettings = "internal:testNotSeen";
        } else {
            includeSettings = "internal:test,internal:testError";
            excludeSettings = "DOESN'T_MATCH";
        }
        clusterSettingsA.applySettings(
            Settings.builder()
                .put(TransportSettings.TRACE_LOG_INCLUDE_SETTING.getKey(), includeSettings)
                .put(TransportSettings.TRACE_LOG_EXCLUDE_SETTING.getKey(), excludeSettings)
                .build()
        );
        MockLogAppender appender = new MockLogAppender();
        try {
            appender.start();
            Loggers.addAppender(LogManager.getLogger("org.elasticsearch.transport.TransportService.tracer"), appender);
            
            
            
            
            appender.addExpectation(
                new MockLogAppender.PatternSeenEventExpectation(
                    "sent request",
                    "org.elasticsearch.transport.TransportService.tracer",
                    Level.TRACE,
                    ".*\\[internal:test].*sent to.*\\{TS_B}.*"
                )
            );