How to generate ETag for static pre-rendered pages in Next.js 15?

Link to the code that reproduces this issue

https://github.com/build24001/static-etag

To Reproduce

1.npm run build
2.npm run start
3.Refresh the homepage
4.Observe that the pre-rendered RSC request is 200 every time

Current vs. Expected behavior

Description:
In Next.js 14, static pre-rendered pages could generate ETags. In Next.js 15, since React Server Components (RSC) are streamed by default, ETags cannot be generated.
Is there any way to disable streaming and enable ETag generation?

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.3.0: Thu Jan  2 20:24:24 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6030
  Available memory (MB): 18432
  Available CPU cores: 12
Binaries:
  Node: 18.20.1
  npm: 10.5.0
  Yarn: N/A
  pnpm: 9.7.0
Relevant Packages:
  next: 15.3.3 // Latest available version is detected (15.3.3).
  eslint-config-next: 15.3.3
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.8.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Loading UI and Streaming

Which stage(s) are affected? (Select all that apply)

Other (Deployed)

Additional context

No response

Use the linked static-etag reproduction: run npm run build, npm run start, and refresh the homepage to confirm the RSC request remains 200. Then investigate whether Next.js 15 exposes a supported way to disable streaming and generate ETags; done means a confirmed configuration or documented limitation.