Provide a mechanism to override `classifyResponseStreaming` behaviour

[hach-que]

Problem Statement

I have a React RSC application that is streaming responses, and classifyResponseStreaming does not correctly detect the HTTP response as a stream because it is limited to only a few content types. I would like to be able to override the detection behaviour so I can avoid spans ending early.

https://github.com/getsentry/sentry-javascript/blob/develop/packages/cloudflare/src/request.ts#L146

Solution Brainstorm

It would be ideal if the Sentry SDK had an optional callback that could be set to inspect a response and return whether or not the response is streaming.

Additional Context

No response

Priority

No response

[linear-code]

JS-3236

[JPeer264]

Hey thanks for the issue.

I have a React RSC application that is streaming responses

I assume it is streaming the RSC or other responses? Which content types were you thinking about? Not sure if adding an option is the best scenario for it.

[hach-que]

@JPeer264 It's streaming RSC and SSR responses. The content types in our case are text/x-component;charset=utf-8 and text/html;charset=utf-8.

SSR is harder to auto-detect because it's text/html. If you don't want to add an option, an alternative could be for Sentry to detect the presence of a custom e.g. x-streaming: true header, we could add that to the responses we know are streaming.

[Lms24]

@hach-que

1. Is text/x-component something you set or is this a standard/set by some framework/library that we should cover?
2. does your text/html response have a content-length header? We already check for test/plain && !contentLength, so maybe we could extend this with text/html.

What I'm trying to determine is if there's an established pattern we're missing or if this is custom and we should provide this override mechanism as you suggested.