update book code

eBook/examples/chapter_6/defer.go

@@ -0,0 +1,17 @@
+package main
+
+import "fmt"
+
+func main() {
+	Function1()
+}
+
+func Function1() {
+	fmt.Printf("In Function1 at the top\n")
+	defer Function2()
+	fmt.Printf("In Function1 at the bottom!\n")
+}
+
+func Function2() {
+	fmt.Printf("Function2: Deferred until the end of the calling function!")
+}