Encode and Write stages look similar

[jotak]

Encoder

type Encoder interface {
	Encode(in []config.GenericMap)
}

Writer

type Writer interface {
	Write(in []config.GenericMap)
}

Shouldn't they be the same?
Or, actually, shouldn't Encoder return an []interface{}, mirroring Decoder ? So that, for instance, we could have a JSON encoder? And the current Prometheus and Kafka encoders would be moved to writers?

[KalmanMeth]

Originally Encoder was not a final stage, and fed into Write (using []interface{}). We changed this to make Encoder a final stage, similar to Write, making encode_prom a final stage. They could now be merged into a single type of stage (called Export or Final or Terminal or whatever).