code: @Override
  	public void afterPropertiesSet() {
  
  		if (this.blockingMongoOperations != null) {
  
  			IndexOperations indexOperations = this.blockingMongoOperations.indexOps(this.collectionName);
  			this.mongoSessionConverter.ensureIndexes(indexOperations);
  		}
  	}
docs: Do not use {@link org.springframework.data.mongodb.core.index.ReactiveIndexOperations} to ensure indexes exist.
  Instead, get a blocking {@link IndexOperations} and use that instead, if possible.