agent/metrics/generic_metrics_client.go
func (gm *GenericMetrics) RecordCall(callID, callName string, callTime time.Time, callStarted chan bool) string {
	if callID == "" {
		hashData := []byte("GenericMetrics-" + callName + strconv.FormatFloat(float64(rand.Float32()), 'f', -1, 32))
		hash := fmt.Sprintf("%x", md5.Sum(hashData))
		// Go routines are utilized to avoid blocking the main thread in case of
		// resource contention with var outstandingCalls
		go gm.FireCallStart(hash, callName, callTime, callStarted)
		go gm.IncrementCallCount(callName)
		return hash
	} else {
		go gm.FireCallEnd(callID, callName, callTime, callStarted)
		return ""
	}
}
func (gm *GenericMetrics) RecordCall(callID, callName string, callTime time.Time, callStarted chan bool) string {
	if callID == "" {
		hashData := []byte("GenericMetrics-" + callName + strconv.FormatFloat(float64(rand.Float32()), 'f', -1, 32))
		hash := fmt.Sprintf("%x", md5.Sum(hashData))
		// Go routines are utilized to avoid blocking the main thread in case of
		// resource contention with var outstandingCalls
		go gm.FireCallStart(hash, callName, callTime, callStarted)
		go gm.IncrementCallCount(callName)
		return hash
	} else {
		go gm.FireCallEnd(callID, callName, callTime, callStarted)
		return ""
	}
}
// This function creates a hash of the callName and a randomly generated number.
// The hash serves to match the call invokation with the call's end, which is
// required to compute the call duration. The final metric is observed when the
// FireCallEnd function is called.
// If callID is empty, then we initiate the call with FireCallStart
// We use a channel holding 1 bool to ensure that the FireCallEnd is called AFTER
// the FireCallStart (because these are done in separate go routines)