I am wondering about how to handle errors when sending data via SSE
Regular HTTP
If for example I want to fetch a User record by id via an http endpoint /users/:id and I encounter a non existing user I would respond with status code 404 and the client would handle it.
SSE
Now I'm wondering how this would look like for SSE. Let's say my endpoint is /users and takes a list of ids ?user_ids=[1, 2, 3]. The endpoint should find each record and send the results one by one. If the user with id 3 cannot be found, what is the protocol to convey this to the client?