discovery/marathon/marathon.go
func (app app) isContainerNet() bool {
	return len(app.Networks) > 0 && app.Networks[0].Mode == "container"
}
func (app app) isContainerNet() bool {
	return len(app.Networks) > 0 && app.Networks[0].Mode == "container"
}
// isContainerNet checks if the app's first network is set to mode 'container'.