func WithSeasonalConfig(conf Config) Opt {
	return func(s *state) {
		s.sConf = conf
	}
}
WithSeasonalConfig configures the seasonal component of the decomposition process.
package stl
import (
	"github.com/chewxy/stl/loess"
)
type Config struct {
	Width int
	Jump int
	Fn loess.WeightUpdate
}
type Opt func(*state)