function pushToStack(type, entry, check) {
    // no entry of given type
    if (typeof stack[type] === "undefined") {
      stack[type] = entry;
    }
    // apply check function
    else if (check(stack[type], entry) === true) {
      stack[type] = entry;
    }
  }
Analyzes HTTP requests and generates stats metrics

setMetric('smallestResponse') @desc the size of the smallest response @offenders
setMetric('biggestResponse') @desc the size of the biggest response @offenders
setMetric('fastestResponse') @desc the time to the last byte of the fastest response @offenders
setMetric('slowestResponse') @desc the time to the last byte of the slowest response @offenders
setMetric('smallestLatency') @desc the time to the first byte of the fastest response @offenders
setMetric('biggestLatency') @desc the time to the first byte of the slowest response @offenders
setMetric('medianResponse') @desc median value of time to the last byte for all responses @offenders
setMetric('medianLatency') @desc median value of time to the first byte for all responses @offenders