Using templates in http sink in vector.dev

Question

I'm using vector.dev to send logs to Parseable. I need to send a header took from log event. For example, if vector receive this log:

{
   "message":"Hello Vector!",
   "service":"education"
}

it should send header:

X-P-Stream: education

I tried to write in config:

request:
  headers:
    X-P-Stream: "{{ .service }}"

But it not works.

How can I do this?