code: function(name, incr /* =1 */ ) {
  		var currVal = this.metrics[name] || 0;
  		incr = incr || 1;
  
  		//debug('incrMetric(%s) += %d', name, incr);
  		this.setMetric(name, currVal + incr);
  	}
docs: increements given metric by given number (default is one)