Create init method on provider interface

vendor/github.com/Microsoft/ApplicationInsights-Go/appinsights/concurrentrandom.go

@@ -0,0 +1,45 @@
+package appinsights
+
+import (
+	"encoding/base64"
+	"math/rand"
+	"sync/atomic"
+	"time"
+	"unsafe"
+)
+
+type concurrentRandom struct {
+	channel chan string
+	random  *rand.Rand
+}
+
+var randomGenerator *concurrentRandom
+
+func newConcurrentRandom() *concurrentRandom {
+	source := rand.NewSource(time.Now().UnixNano())
+	return &concurrentRandom{
+		channel: make(chan string, 4),
+		random:  rand.New(source),
+	}
+}
+
+func (generator *concurrentRandom) run() {
+	buf := make([]byte, 8)
+	for {
+		generator.random.Read(buf)
+		generator.channel <- base64.StdEncoding.EncodeToString(buf)
+	}
+}
+
+func randomId() string {
+	if randomGenerator == nil {
+		r := newConcurrentRandom()
+		if atomic.CompareAndSwapPointer((*unsafe.Pointer)(unsafe.Pointer(&randomGenerator)), unsafe.Pointer(nil), unsafe.Pointer(r)) {
+			go r.run()
+		} else {
+			close(r.channel)
+		}
+	}
+
+	return <-randomGenerator.channel
+}