add h2 header manually for pre-go 1.9 users when manually key files are being used

Former-commit-id: edf521fc02de87b53cd3bdf0b8e77610dd535862

_examples/routing/writing-a-middleware/globally/main.go

@@ -0,0 +1,56 @@
+package main
+
+import "github.com/kataras/iris"
+
+func main() {
+	app := iris.New()
+	// register the "before" handler as the first handler which will be executed
+	// on all domain's routes.
+	// or use the `UseGlobal` to register a middleware which will fire across subdomains.
+	app.Use(before)
+	// register the "after" handler as the last handler which will be executed
+	// after all domain's routes' handler(s).
+	app.Done(after)
+
+	// register our routes.
+	app.Get("/", indexHandler)
+	app.Get("/contact", contactHandler)
+
+	app.Run(iris.Addr(":8080"))
+}
+
+func before(ctx iris.Context) {
+	shareInformation := "this is a sharable information between handlers"
+
+	requestPath := ctx.Path()
+	println("Before the indexHandler or contactHandler: " + requestPath)
+
+	ctx.Values().Set("info", shareInformation)
+	ctx.Next()
+}
+
+func after(ctx iris.Context) {
+	println("After the indexHandler or contactHandler")
+}
+
+func indexHandler(ctx iris.Context) {
+	println("Inside indexHandler")
+
+	// take the info from the "before" handler.
+	info := ctx.Values().GetString("info")
+
+	// write something to the client as a response.
+	ctx.HTML("<h1>Response</h1>")
+	ctx.HTML("<br/> Info: " + info)
+
+	ctx.Next() // execute the "after" handler registered via `Done`.
+}
+
+func contactHandler(ctx iris.Context) {
+	println("Inside contactHandler")
+
+	// write something to the client as a response.
+	ctx.HTML("<h1>Contact</h1>")
+
+	ctx.Next() // execute the "after" handler registered via `Done`.
+}