Hey @lukapor, thank you for this. Your PR inspired #748, which defines a SimilarityDescriptor and provides the ability to set similarities via the fluent API approach that all our descriptors take.

Regarding your change to SortFieldDescriptor, I believe ToggleSort is correct the way it is. It's toggling the sort order, not just setting it- so if the current order is Ascending, then it would be correct to change it to Descending.

Thanks again for your PR, sorry I couldn't merge it in!

Hey ok it is maybe confusing method name, but it isn't consistent with same function in SortScriptDescriptor.cs and SortFieldDescriptor.cs. Please check it.

And SortGeoDistanceDescriptor.cs file.

@lukapor You are totally right, thanks for pointing that out. ToggleSort is completely confusing. I just opened PR #764 which replaces ToggleSort() with Order() and takes the SortOrder enum instead of a bool. I think that's much clearer and just as effective- what do you think?

That is great. Thanks.