Is your feature request related to a problem? Please describe.
For log processing applications like sumologic, key value pair encoding is fastest. I want to raise an MR for keyvalue encoder, over the ones that are already available: json and console.

Describe the solution you'd like
I can raise a PR for this new encoder.

Describe alternatives you've considered
Currently people have to copy paste code of json encoder and implement all it's code, as it is not exported.

Is this a breaking change?
no