// Send method sends an Heartbeat Signal to OpsGenie.
func (cli *OpsGenieHeartbeatClient) Send(req heartbeat.SendHeartbeatRequest) (*heartbeat.SendHeartbeatResponse, error) {
	req.APIKey = cli.apiKey
	resp, err := cli.sendRequest(cli.buildPostRequest(sendHeartbeatURL, req))

	if resp == nil {
		return nil, err
	}
	defer resp.Body.Close()

	var sendHeartbeatResp heartbeat.SendHeartbeatResponse
	if err = resp.Body.FromJsonTo(&sendHeartbeatResp); err != nil {
		message := "Server response can not be parsed, " + err.Error()
		logging.Logger().Warn(message)
		return nil, errors.New(message)
	}

	return &sendHeartbeatResp, nil
}