## Summary
We have adapted our edge services to better know when they should flush on write. This is an important
feature to ensure response types like Server Side Events are not buffered, and instead are propagated to the eyeball
as soon as possible. This commit implements a similar logic for http2 tunnel protocol that we use in our edge
services. By adding the new events stream header for json `application/x-ndjson` and using the content-length
and transfer-encoding headers as well, following the RFC's:
- https://datatracker.ietf.org/doc/html/rfc7230#section-4.1
- https://datatracker.ietf.org/doc/html/rfc9112#section-6.1
Closes TUN-9255
73a9980f38