[FEATURE] i want to add a meta(map[string]interface{}) fields on BulkIndexerItem, for OnSuccess callback

[pwm1992]

Is your feature request related to a problem?

when I use bulk request to create doc, I want to modify some extraData on CallBack func (onSuccess/OnFailed)

What solution would you like?

add a meta(map[string]interface{})

What alternatives have you considered?

no

Do you have any additional context?

use the opensearch bulk to consume log(file) for batch create doc， i want to implement resume from break-point for the file. so, i have to know about each file offset of doc when I create doc success. but the file offset is extradata， so i want to add the metadata

[dblock]

This is a reasonable suggestion. Want to give it a try @pwm1992?