ETag support

[privatenumber]

• Operating System: Mac
• Node Version: v12.16.2
• NPM Version: v6.14.4
• webpack Version: v4.44.2
• webpack-dev-middleware Version: v3.7.2

Feature Proposal

Add Etags to assets to prevent re-loading unchanged assets.

Feature Use Case

Faster page loads by eliminating loads for large files that are unchanged.

This optimization is used in other dev bundlers like Vite and Snowpack.

Other

I implemented this via wrapper in a separate package.

Happy to open a PR if the issue is accepted.

[alexander-akait]

@privatenumber Yes, PR welcome

[privatenumber]

Is v3 still actively maintained? I didn't see a separate dev branch for it but I'm personally using v3 so I would like to add it there so that I can use it.

If not, I can add it to v4.

[alexander-akait]

Yes, let's add to v4, I will do release in near future (today/tomorrow), also v4 supports webpack@4 and webpack@5