function Metric(key, tags, host) {
    this.key = key;
    this.tags = tags || [];
    this.host = host || '';
}
function Metric(key, tags, host) {
    this.key = key;
    this.tags = tags || [];
    this.host = host || '';
}
function Metric ( key , tags , host ) { this . key = key ; this . tags = tags || [ ] ; this . host = host || '' ; }
--- Metric (base class)
--- Metric ( base class )