query.go
func (q *Query) WaitTrigger(event string) *Query {
	q.headers = append(q.headers, "WaitTrigger: "+event)
	return q
}
func (q *Query) WaitTrigger(event string) *Query {
	q.headers = append(q.headers, "WaitTrigger: "+event)
	return q
}
// WaitTrigger appends a new wait trigger to the query, waiting for a specific event broker message to recheck
// condition.