refactor(event): make _res and res._headers hidden

[huseeiin]

this hides props from the user that they should not use

[pi0]

Thanks for PR. It breaks tests since in response handler we need to access intermediate headers and avoid triggering slow path:

h3/src/response.ts

Line 72 in 8972b0f

const eventHeaders = (event.res as { _headers?: Headers })._headers;

We could use ~ instead.

[huseeiin]

Thanks for PR. It breaks tests since in response handler we need to access intermediate headers and avoid triggering slow path:

h3/src/response.ts

Line 72 in 8972b0f

const eventHeaders = (event.res as { _headers?: Headers })._headers;

We could use ~ instead.

oh this line will error?