Undefined: publisher.Client missing from go imports

I followed the beats tutorial at https://www.elastic.co/guide/en/beats/devguide/current/beater-interface.html and my go file gives an error at publisher.Client() ... obviously the import is missing.

my imports:
import (
"fmt"
"time"

"github.com/elastic/beats/libbeat/publisher"

"github.com/dakoller/awscostbeat/config"
"github.com/elastic/beats/libbeat/beat"
"github.com/elastic/beats/libbeat/common"
"github.com/elastic/beats/libbeat/logp"

)

..any idea where the publisher import can be found?

(beats 7.4 / mac os)