Don't automatically do concurrency for users

http://talks.golang.org/2013/bestpractices.slide#25

id.go

@@ -18,15 +18,16 @@ type IdGenerator struct {
 }
 
 func NewIdGenerator() *IdGenerator {
-	g := IdGenerator{}
-	g.id = make(chan int64)
-	go func() {
-		var i int64
-		for i = 0; ; i++ {
-			g.id <- i
-		}
-	}()
-	return &g
+	return &IdGenerator{
+		id: make(chan int64),
+	}
+}
+
+func (idg *IdGenerator) Run() {
+	var i int64
+	for i = 0; ; i++ {
+		idg.id <- i
+	}
 }
 
 func (id *IdGenerator) Hash() string {

id_test.go

@@ -8,6 +8,7 @@ func TestIDGenerator(t *testing.T) {
 	cache := make(map[string]bool)
 	var cur string
 	gg := NewIdGenerator()
+	go gg.Run()
 	for i := 0; i < 10000; i++ {
 		cur = gg.Hash()
 		if _, ok := cache[cur]; ok {