series.go
func (client *Client) PostMetrics(series []Metric) error {
	return client.doJsonRequest("POST", "/v1/series",
		reqPostSeries{Series: series}, nil)
}
func (client *Client) PostMetrics(series []Metric) error {
	return client.doJsonRequest("POST", "/v1/series",
		reqPostSeries{Series: series}, nil)
}
// PostMetrics takes as input a slice of metrics and then posts them up to the
// server for posting data.