Refactor `AbstractSimpleTransportTestCase` and `MockTransportService` to not use `Version.transportVersion` 
test/framework/src/main/java/org/elasticsearch/transport/AbstractSimpleTransportTestCase.java
throw new UncheckedIOException(e1);
                    }
                }
                @Override
                protected void doRun() throws Exception {
                    receivedLatch.countDown();
                    sendResponseLatch.await();
                    onFailure(ex);
                }
            });
        });
        CountDownLatch responseLatch = new CountDownLatch(1);
        AtomicReference<TransportException> receivedException = new AtomicReference<>(null);
        TransportResponseHandler<TransportResponse.Empty> transportResponseHandler = new TransportResponseHandler.Empty() {
            @Override
            public void handleResponse(TransportResponse.Empty response) {
                responseLatch.countDown();
            }
            @Override
            public void handleException(TransportException exp) {
                receivedException.set(exp);
                responseLatch.countDown();
            }
        };
        TransportStats stats = serviceC.transport.getStats(); 
        assertEquals(0, stats.getRxCount());
        assertEquals(0, stats.getTxCount());
        assertEquals(0, stats.getRxSize().getBytes());
        assertEquals(0, stats.getTxSize().getBytes());
        ConnectionProfile.Builder builder = new ConnectionProfile.Builder();