### 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(StringMessageResponse response) {}
                @Override
                public void handleException(TransportException exp) {
                    logger.error("Unexpected failure", exp);
                    fail("got exception instead of a response: " + exp.getMessage());
                }
            };
            Future<StringMessageResponse> compressed = submitRequest(
                serviceC,
                serviceA.getLocalDiscoNode(),
                "internal:sayHello",
                new StringMessageRequest(text, -1, true),
                responseHandler
            );
            Future<StringMessageResponse> uncompressed = submitRequest(
                serviceA,
                serviceC.getLocalDiscoNode(),
                "internal:sayHello",
                new StringMessageRequest(text, -1, false),
                responseHandler
            );
            compressed.get();
            uncompressed.get();
            final long bytesLength;
            try (BytesStreamOutput output = new BytesStreamOutput()) {
                new StringMessageRequest(text, -1).writeTo(output);
                bytesLength = output.bytes().length();
            }