SSE passthrough broken

[alanknight-wk]

Or else is causing a problem with micro-frontends.

Building the wdesk sdk example app it will not reload properly if one of the micro-frontends is built with DDC. If I use --no-injected-client it's fine. To reproduce just run the app, then reload localhost:8080

webdev 2.4.0
webdev_proxy 0.1.0
dart 2.7.2, 2.11.0-277.0.dev

[alanknight-wk]

I checked by re-activating webdev 2.4.0, and that it got dwds 0.5.5, and this still happens. So it doesn't seem to be related to the change to SEE endpoints in October 2020.