[kong 2.8.1] custom plugin, function response return signal 11 for nginx worker

[salvadoriume]

Hello,
I use kong 2.8.1 image.
I tried to use in custom plugin new function response() which join header_filter and body_filter
(access phase).
When it is defined and then I make a request with header "If-Match" nginx worker quits with signal 11.
Do you have any working example (or can example Kong/kong-plugin be updated to new form) or it should be treated as a bug?

When I change to body_filter() all works.

How I tested it:
echo '{ "user": { "name": "john", "age": 10 } }' | http POST "localhost:8000/api/v1/test?echo_code=200" 'If-Match: 23'

route points to echoserver container. I want to pass "If-match" to it, not to be handled on kong layer.

[salvadoriume]

Used image https://hub.docker.com/r/ealen/echo-server to create test route - but it doesn't matter what is behind that route.
Request with such header:

• exit nginx worker with signal 11
• response to client with http code 412