bulk helper add onSuccess callback

[zivni]

🚀 Feature Proposal

The bulk helper API gives onDrop callback that is called when the document can’t be indexed.

Is it possible to add an onSuccess callback or onIndex callback that will be called when the document is indexed successfully?

Motivation

When uploading from other source a lot of documents using a stream or generator I want to mark the documents that where actually indexed so if the program crashes it can be resumed from the point of failure.