add Context.SendFileWithRate, ServeFileWithRate and ServeContentWithRate

as requested at: https://github.com/kataras/iris/issues/1493


Former-commit-id: 7783fde04b4247056e6309e7ec1df27f027dc655

_examples/README.md

@@ -237,7 +237,7 @@ You can serve [quicktemplate](https://github.com/valyala/quicktemplate) and [her
 - [Basic](file-server/basic/main.go)
 - [Embedding Files Into App Executable File](file-server/embedding-files-into-app/main.go)
 - [Embedding Gziped Files Into App Executable File](file-server/embedding-gziped-files-into-app/main.go)
-- [Send/Force-Download Files](file-server/send-files/main.go)
+- [Send/Force-Download Files](file-server/send-files/main.go) **UPDATED**
 - Single Page Applications
     * [single Page Application](file-server/single-page-application/basic/main.go)
     * [embedded Single Page Application](file-server/single-page-application/embedded-single-page-application/main.go)
@@ -246,7 +246,7 @@ You can serve [quicktemplate](https://github.com/valyala/quicktemplate) and [her
 ### How to Read from `context.Request() *http.Request`
 
 - [Read JSON](http_request/read-json/main.go)
-    * [Struct Validation](http_request/read-json-struct-validation/main.go) **UPDaTE**
+    * [Struct Validation](http_request/read-json-struct-validation/main.go) **UPDATED**
 - [Read XML](http_request/read-xml/main.go)
 - [Read MsgPack](http_request/read-msgpack/main.go) **NEW**
 - [Read YAML](http_request/read-yaml/main.go)

_examples/file-server/send-files/main.go

@@ -6,11 +6,26 @@ import (
 
 func main() {
 	app := iris.New()
+	app.Logger().SetLevel("debug")
 
-	app.Get("/", func(ctx iris.Context) {
-		file := "./files/first.zip"
-		ctx.SendFile(file, "c.zip")
-	})
+	app.Get("/", download)
+	app.Get("/download", downloadWithRateLimit)
 
 	app.Listen(":8080")
 }
+
+func download(ctx iris.Context) {
+	src := "./files/first.zip"
+	ctx.SendFile(src, "client.zip")
+}
+
+func downloadWithRateLimit(ctx iris.Context) {
+	// REPLACE THAT WITH A BIG LOCAL FILE OF YOUR OWN.
+	src := "./files/first.zip"
+	dest := "" /* optionally, keep it empty to resolve the filename based on the "src" */
+
+	// Limit download speed to ~50Kb/s with a burst of 100KB.
+	limit := 50.0 * iris.KB
+	burst := 100 * iris.KB
+	ctx.SendFileWithRate(src, dest, limit, burst)
+}

_examples/http_responsewriter/write-gzip/main.go

@@ -4,6 +4,9 @@ import "github.com/kataras/iris/v12"
 
 func main() {
 	app := iris.New()
+	// app.Use(iris.Gzip)
+	// func(ctx iris.Context) { ctx.Gzip(true/false)}
+	// OR:
 	app.Get("/", func(ctx iris.Context) {
 		ctx.WriteGzip([]byte("Hello World!"))
 		ctx.Header("X-Custom",