func (c *Controller) Loop() error {
	timer.Delay(500)
	serial.Println("  Write PIN 2 -> HIGH")
	digital.Write(2, digital.High)
	timer.Delay(500)
	digital.Write(2, digital.Low)
	serial.Println("  Write PIN 2 -> LOW")
	return nil
}
Loop code will be called repeatedly.
package device
import (
	controller "github.com/andygeiss/esp32-controller"
	"github.com/andygeiss/esp32-controller/digital"
	"github.com/andygeiss/esp32-controller/serial"
	"github.com/andygeiss/esp32-controller/timer"
)
type Controller struct {
}
func NewController() controller.Controller {
	return &Controller{}
}