emit warnings in swc plugin

[AmalJossy]

The error reporting section of plugin cheatsheet from swc docs point to HANDLER for error reporting.
I tried using struct_span_warn but the warning doesn't print at all. If I switch to struct_span_err the error prints but the errors are reported at the end of webpack compilation.
If I add a simple println! the warning prints immediately.

• How do I allow warnings from an swc plugin?
  • do I have to change can_emit_warnings flag? (allow warnings attr didn't work)
    • is there an example for changing the handlers flags?
• How do I get the warning/err to print immediately like println!