4.2.1

• Remove workers from indexer.NewBulkIndexer methods
• Add Verbose flag to indexer.BulkIndexerOptions to allow tracking of updates
• Technically this release is backwards incompatible because of changes to the method signature indexer.NewBulkIndexer. Since we're trying to keep the major version number for this package in sync with opensearch-go it is just one of life's little injustices we will have to suffer...