fast reload (without restart) like Next.js

### Prerequisites

- [X] I have written a descriptive issue title
- [X] I have searched existing issues to ensure the feature has not already been requested

### 🚀 Feature Proposal

Hi, my project has a lot of routes ~100 routes and ~150 dependencies. And everything is slowing down.
I used all tools `nodemon` , `ts-node`, `ts-node-dev`, `backpack` and `fastify-cli` (v4)
I even purchase a new good CPU with a benchmark score is 24000
But my project still takes 4-5s to restart when a file is changed.

I am using Next.js too. And I am curious why Next.js never needs to restart the server, but other node.js frameworks can't do that 🤔

### Motivation

Everyone is happy.

### Example

_No response_