client/events.go
func (e *EventListener) AddHandler(types []string, function func(api.Event)) (*EventTarget, error) {
	if function == nil {
		return nil, fmt.Errorf("A valid function must be provided")
	}

	// Handle locking
	e.targetsLock.Lock()
	defer e.targetsLock.Unlock()

	// Create a new target
	target := EventTarget{
		function: function,
		types:    types,
	}

	// And add it to the targets
	e.targets = append(e.targets, &target)

	return &target, nil
}
func (e *EventListener) AddHandler(types []string, function func(api.Event)) (*EventTarget, error) {
	if function == nil {
		return nil, fmt.Errorf("A valid function must be provided")
	}

	// Handle locking
	e.targetsLock.Lock()
	defer e.targetsLock.Unlock()

	// Create a new target
	target := EventTarget{
		function: function,
		types:    types,
	}

	// And add it to the targets
	e.targets = append(e.targets, &target)

	return &target, nil
}
// AddHandler adds a function to be called whenever an event is received