Initial work on new guide

guide/heap.go

@@ -0,0 +1,28 @@
+// +build ignore
+
+package main
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+)
+
+func main() {
+	var (
+		sum int32
+		wg  = &sync.WaitGroup{}
+	)
+
+	wg.Add(2)
+	go add(&sum, 23, wg)
+	go add(&sum, 42, wg)
+	wg.Wait()
+
+	fmt.Println(sum)
+}
+
+func add(dst *int32, delta int32, wg *sync.WaitGroup) {
+	atomic.AddInt32(dst, delta)
+	wg.Done()
+}