in health_metric_collector/src/sys_info_collector.cpp [42:50]
void SysInfoCollector::AddMetric(const std::string & name, const double value,
const std::string & unit)
{
MetricData md = mgr_->CreateMetric();
md.metric_name = name;
md.unit = unit;
md.value = value;
mgr_->AddMetric(md);
}