func (p *Emitter) Off(event string, handler EventHandler) {
	p.emitter.Off(event, handler)
}
Off remove a listener function, pointer of the function passed must match with the one
package emitter
import (
	"github.com/chuckpreslar/emission"
)
type EventHandler func(interface{})
func NewEmitter() Emitter {
	return Emitter{
		emitter: emission.NewEmitter(),
	}
}
type Emitter struct {
	emitter *emission.Emitter
}
func (p *Emitter) Emit(event string, data interface{}) {
	p.emitter.Emit(event, data)
}
func (p *Emitter) On(event string, handler EventHandler) {
	p.emitter.On(event, handler)
}