[MetricBeat] aws module cloudwatch metricset fetch all regions metrics concurrently

[kwinstonix]

Describe the enhancement:

There are two for loops in Fetch function. If each region has many metrics and period is small(e.g. 1m), events are reported slowly.

Is it possible to use goroutine instead of for loop ?

beats/x-pack/metricbeat/module/aws/cloudwatch/cloudwatch.go

Lines 145 to 153 in d043a69

	return err
	}
	// Create events based on listMetricDetailTotal from configuration
	if len(listMetricDetailTotal.metricsWithStats) != 0 {
	for _, regionName := range m.MetricSet.RegionsList {
	//m.logger.Debugf("Collecting metrics from AWS region %s", regionName)
	beatsConfig := m.MetricSet.AwsConfig.Copy()
	beatsConfig.Region = regionName

beats/x-pack/metricbeat/module/aws/cloudwatch/cloudwatch.go

Lines 173 to 179 in d043a69

	// Create events based on namespaceDetailTotal from configuration
	for _, regionName := range m.MetricSet.RegionsList {
	m.logger.Debugf("Collecting metrics from AWS region %s", regionName)
	beatsConfig := m.MetricSet.AwsConfig.Copy()
	beatsConfig.Region = regionName
	svcCloudwatch, svcResourceAPI, err := m.createAwsRequiredClients(beatsConfig, regionName, config)

[botelastic]

This issue doesn't have a Team:<team> label.

[botelastic]

Hi!
We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1.
Thank you for your contribution!