cloudflared/vendor/github.com/aws/aws-sdk-go/aws/csm/metric_chan.go

package csm

import (
	"sync/atomic"
)

const (
	runningEnum = iota
	pausedEnum
)

var (
	// MetricsChannelSize of metrics to hold in the channel
	MetricsChannelSize = 100
)

type metricChan struct {
	ch     chan metric
	paused *int64
}

func newMetricChan(size int) metricChan {
	return metricChan{
		ch:     make(chan metric, size),
		paused: new(int64),
	}
}

func (ch *metricChan) Pause() {
	atomic.StoreInt64(ch.paused, pausedEnum)
}

func (ch *metricChan) Continue() {
	atomic.StoreInt64(ch.paused, runningEnum)
}

func (ch *metricChan) IsPaused() bool {
	v := atomic.LoadInt64(ch.paused)
	return v == pausedEnum
}

// Push will push metrics to the metric channel if the channel
// is not paused
func (ch *metricChan) Push(m metric) bool {
	if ch.IsPaused() {
		return false
	}

	select {
	case ch.ch <- m:
		return true
	default:
		return false
	}
}