Apply suggestions from code review

Co-authored-by: Valentin Kovalenko <[email protected]>

Author: vbabanin

driver-reactive-streams/src/main/com/mongodb/reactivestreams/client/internal/MongoClusterImpl.java

@@ -269,9 +269,13 @@ public Publisher<ClientBulkWriteResult> bulkWrite(final ClientSession clientSess
 
     @Override
     public Publisher<ClientBulkWriteResult> bulkWrite(final ClientSession clientSession,
-                                                      final List<? extends ClientNamespacedWriteModel> models,
-                                                      final ClientBulkWriteOptions options) throws ClientBulkWriteException {
-        return mongoOperationPublisher.clientBulkWrite(clientSession, models, options);
+                                                      final List<? extends ClientNamespacedWriteModel> clientWriteModels,
+                                                      final ClientBulkWriteOptions options) {
+        notNull("clientSession", clientSession);
+        notNull("clientWriteModels", clientWriteModels);
+        isTrueArgument("`clientWriteModels` must not be empty", !clientWriteModels.isEmpty());
+        notNull("options", options);
+        return mongoOperationPublisher.clientBulkWrite(clientSession, clientWriteModels, options);
     }
 
 }

driver-reactive-streams/src/main/com/mongodb/reactivestreams/client/internal/MongoOperationPublisher.java

@@ -292,6 +292,7 @@ Publisher<BulkWriteResult> bulkWrite(
                 operations::getTimeoutSettings,
                 () -> operations.bulkWrite(notNull("requests", requests), notNull("options", options)), clientSession);
     }
+
     Publisher<ClientBulkWriteResult> clientBulkWrite(
             @Nullable final ClientSession clientSession,
             final List<? extends ClientNamespacedWriteModel> clientWriteModels,