[Backport 6.x] Implement meta header for client requests #5302
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backport fec16ef from #5190
@Mpdreamz This backports the work in 7.x for the meta header to 6.x. Some changes had to be made to get it to compile and function. A few types needed to be made public rather than internal as it seems NEST cannot use Elasticsearch.NET internals in 6.x. Integration tests work as expected against latest-6 and all unit tests are passing. I observed the header on the integration test requests.