Output message as json

[kk-mats]

Hi, I started to use this package in conjuction with logback-logstash-encoder for message layout.
Then I noticed that message is output being quoted as string even if it is actually json.

I suppose this is because EcsJsonSerializer.serializeFormattedMessage is always used for any message layout in EcsEncorder.
https://github.com/elastic/ecs-logging-java/blob/main/logback-ecs-encoder/src/main/java/co/elastic/logging/logback/EcsEncoder.java#L149

Currently is there any way to output message in json or do you have any plan to support such feature?

[felixbarny]

You could parse the JSON message in an Elasticsearch ingest pipeline. But generally, the ecs encoder is not designed to work with another JSON encoder.