Exposing the regular fields in SearchHit

[astefan]

At the moment, internal clients of SearchHit can only get a list of all fields (regular and metadata) inside a hit, even if those are separated as metadataFields and documentFields. Filtering out metadata fields is not so straightforward and a dedicated method would be preferred.

[elasticmachine]

Pinging @elastic/es-search (Team:Search)

[romseygeek]

It looks as though the only non-test consumers of getFields() are EventPayload and SequencePayload. Do both of these classes only want non-metadata fields? In which case we can just switch getFields() to only return doc fields. Alternatively, we can rename it to getAllFields(), and two new methods to get doc fields and metadata fields, and then cut over other uses in a followup.

[astefan]

Before the fields API was introduced, we were looking at the "ignored" fields in the response, but now I don't think we need this information. That's the only connection between QL and "ignored" fields that I'm aware of.
EventPayload and SequencePayload return this information to the user and, since fields API doesn't allow metadata fields to be returned, I think it's safe to say that we need only non-metadata fields.

[cbuescher]

the only non-test consumers of getFields() are EventPayload and SequencePayload.

I think that a lot of client side code might accesses this method outside of the ES codebase. Rather than changing the existing behaviour or the naming I would add new methods for this reasion. Just my 10c though.