TotalRequests  int64
	FailedRequests int64
}

// TargetList - holds list of targets indexed by target ID.
type TargetList struct {
	sync.RWMutex
	targets map[TargetID]Target
}

// Add - adds unique target to target list.
func (list *TargetList) Add(targets ...Target) error {
	list.Lock()
	defer list.Unlock()

	for _, target := range targets {
		if _, ok := list.targets[target.ID()]; ok {

		stats = targetStat{}
	}

	stats.totalEvents++
	list.targetStats[id] = stats
	return
}

type asyncEvent struct {
	ev        Event
	targetSet TargetIDSet
}

// Add - adds unique target to target list.
func (list *TargetList) Add(targets ...Target) error {
	list.Lock()
	defer list.Unlock()

	for _, target := range targets {
		if _, ok := list.targets[target.ID()]; ok {