[middleware/filesystem]: Set response code

[cuipeiyu]

A tiny Demo

package main

import (
	"net/http"

	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/fiber/v2/middleware/filesystem"
)

func main() {
	app := fiber.New()
	app.Use(
		"/",
		filesystem.New(filesystem.Config{
			Root: http.Dir("./try-a"),
		}),
		filesystem.New(filesystem.Config{
			Root: http.Dir("./try-b"),
		}),
	)

	app.Listen(":http")
}

$ tree
.
├── main.go
├── try-a
└── try-b
    └── index.html

3 directories, 2 files

Wrong response code 404

$ curl -I http://localhost/index.html
HTTP/1.1 404 Not Found
Date: Wed, 13 Sep 2023 04:16:23 GMT
Content-Type: text/html
Content-Length: 201
Last-Modified: Wed, 13 Sep 2023 04:00:02 GMT

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