createClient
Creates a MongoClient instance with default connection string (localhost).
Creates a MongoClient with the given connection string.
Creates a MongoClient with the given settings (the codec registry is updated with KMongo mapping).
Wraps a Java sync driver client in a Kotlin sync driver client (they share the same connection pool, closing one closes the other).
The codec registry of the Java client is not modified: create it with createJavaClient to use the KMongo mapping.