func (res *AnnotationsResponse) WriteAnnotation(a grafana.Annotation) {
	res.Annotations = append(res.Annotations, a)
}
WriteAnnotation satisfies the grafana.AnnotationsResponse interface.
package grafanatest
import "github.com/segmentio/stats/v4/grafana"
type AnnotationsResponse struct {
	Annotations []grafana.Annotation
}