Sending file with 404 status code dont work

[CZmatyasZERO]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

5.0.0

Plugin version

8.0.1

Node.js version

20.9.0

Operating system

Windows

Operating system version (i.e. 20.04, 11.3, 10)

11

Description

Sending file with 404 status code dont work, see the code below.
On fastify version 4.28.1 and plugin version this worked normally.

const fastify = require('fastify')({logger: true})
const path = require('node:path')

fastify.register(require('@fastify/static'), {
  root: path.join(__dirname, 'public'),
  prefix: '/',
})


fastify.setNotFoundHandler((req, reply) => {
  return reply.code(404).type("text/html").sendFile("404.html")
  // this send the file with 200 status code
})

// Run the server!
fastify.listen({ port: 3000 })

const fastify = require('fastify')({logger: true})
const path = require('node:path')

fastify.register(require('@fastify/static'), {
  root: path.join(__dirname, 'public'),
  prefix: '/',
})


fastify.setNotFoundHandler((req, reply) => {
  return reply.code(404).type("text/html").send("Hello world")
  // this send the Hello world message with 404 status code
})

// Run the server!
fastify.listen({ port: 3000 })

Link to code that reproduces the bug

No response

Expected Behavior

It should send file with 404 status code.