client.go
func (c *Client) TriggerExclusive(channel string, eventName string, data interface{}, socketID string) (*BufferedEvents, error) {
	return c.trigger([]string{channel}, eventName, data, &socketID)
}
func (c *Client) TriggerExclusive(channel string, eventName string, data interface{}, socketID string) (*BufferedEvents, error) {
	return c.trigger([]string{channel}, eventName, data, &socketID)
}
/*
This method allow you to exclude a recipient whose connection has that
`socket_id` from receiving the event. You can read more here: http://pusher.com/docs/duplicates.

	client.TriggerExclusive("a_channel", "event", data, "123.12")

*/