Invalid message sent to STDOUT

This message validation failed on the message sent to STDOUT, RR docs: https://roadrunner.dev/docs/known-issues-stdout-crc/2.x/en, invalid message: ... means that you or some application sent a non-correct message (raw) to the STDOUT.
Process STDOUT is reserved for the RR communication with the PHP process via the goridge protocol (v3).

How to fix that?

1. Check your application. All dependencies should send their messages to the STDERR instead of STDOUT. You may see the output after the invalid message. It might be shrunk on windows.
2. Check dd , echo inserted by you. PHP workers can redirect echo automatically from the STDOUT to STDERR but only after the worker is initialized fully.
3. Worker from the RRv1 was used. To update, see: https://roadrunner.dev/docs/integration-migration/2.x/en
4. OPcache enabled with JIT, but some extenstion doesn't support it, which leads to the warnings. Tune the error_reporting configuration option (use only errors): issue
5. If you use a Symfony runtime, do not forget to add APP_RUNTIME to the server environment variables, as described here: https://github.com/php-runtime/roadrunner-symfony-nyholm.