Server Sent Events stream get buffered when not using EventSource

[leilengma]

Current behavior

When connecting to a server sent event endpoint:

• events arrive correctly and on time with EventSource object
• no event arrives when using fetch api for the connection until the server closes the connection -> looks like cypress is buffering the content in background

Desired behavior

It shouldn't be matter whether fetch or EventSource is chosen for a Server Sent Event api connection. Events should arrive on time and not get buffered.

Test code to reproduce

checkout this repo https://github.com/leilengma/cypress-sse-issue
npm install and lunch cypress
start the default test case and open console in browser

You can only see logs from the eventsource object
open chrome and visit http://localhost:3008 and then open console

you can see logs from both eventsource and fetch

Cypress Version

13.16.0

Node version

v20.17.0

Operating System

windows 10

Debug Logs

No response

Other

No response