messages.go
func (m *MessageService) GetPage(ctx context.Context, data url.Values) (*MessagePage, error) {
	iter := m.GetPageIterator(data)
	return iter.Next(ctx)
}
func (m *MessageService) GetPage(ctx context.Context, data url.Values) (*MessagePage, error) {
	iter := m.GetPageIterator(data)
	return iter.Next(ctx)
}
// GetPage returns a single page of resources. To retrieve multiple pages, use
// GetPageIterator.