This page documents some interesting options for wait: a ?refresh=wait_for and ?refresh=false options to wait for a specific document operation to be applied, or explicitly skip waiting for one operation.

While here it mentions "To alter this behavior per operation, the wait_for_active_shards request parameter can be used." -> looks like some tuning can be done on a per-setting base, maybe more?

In the case of the translog settings, maybe we don't even need this: It's reasonable to expect to log at least an error message when an operation failed; we need to take advantage of the async design of the new Elasticsearch client to keep pushing more indexing operations while performing batch indexing, but still have an error-handler context attached to the older operations which have been sent but not ACKed yet.