Marked some classes as final

direct-impl/src/main/java/com/microsoft/azure/cosmosdb/internal/directconnectivity/rntbd/RntbdRequestRecord.java

@@ -38,7 +38,7 @@ import java.util.concurrent.TimeUnit;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 
-public class RntbdRequestRecord extends CompletableFuture<StoreResponse> {
+public final class RntbdRequestRecord extends CompletableFuture<StoreResponse> {
 
     private final RntbdRequestArgs args;
     private final RntbdRequestTimer timer;

direct-impl/src/main/java/com/microsoft/azure/cosmosdb/internal/directconnectivity/rntbd/RntbdServiceEndpoint.java

@@ -55,7 +55,7 @@ import java.util.stream.Stream;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.microsoft.azure.cosmosdb.internal.directconnectivity.RntbdTransportClient.Metrics;
 
-public class RntbdServiceEndpoint implements RntbdEndpoint {
+public final class RntbdServiceEndpoint implements RntbdEndpoint {
 
     private static final String className = RntbdServiceEndpoint.class.getCanonicalName();
     private static final AtomicLong instanceCount = new AtomicLong();

direct-impl/src/test/java/com/microsoft/azure/cosmosdb/internal/directconnectivity/RntbdTransportClientTest.java

@@ -85,7 +85,7 @@ import static com.microsoft.azure.cosmosdb.internal.HttpConstants.SubStatusCodes
 import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;
 
-public class RntbdTransportClientTest {
+public final class RntbdTransportClientTest {
 
     private static final Logger logger = LoggerFactory.getLogger(RntbdTransportClientTest.class);
     private static final int lsn = 5;