func (q *Query) Comment(comment string) *Query {
	q.m.Lock()
	q.op.options.Comment = comment
	q.op.hasOptions = true
	q.m.Unlock()
	return q
}
func (q *Query) Comment(comment string) *Query {
	q.m.Lock()
	q.op.options.Comment = comment
	q.op.hasOptions = true
	q.m.Unlock()
	return q
}
// Comment adds a comment to the query to identify it in the database profiler output.
//
// Relevant documentation:
//
//     http://docs.mongodb.org/manual/reference/operator/meta/comment
//     http://docs.mongodb.org/manual/reference/command/profile
//     http://docs.mongodb.org/manual/administration/analyzing-mongodb-performance/#database-profiling
//