--On Master
CREATE TABLE test (id SERIAL PRIMARY KEY, msg TEXT NOT NULL);
CREATE PUBLICATION testpub FOR TABLE test

--On Replica
CREATE TABLE test (id SERIAL PRIMARY KEY, msg TEXT NOT NULL);
CREATE SUBSCRIPTION testsub CONNECTION 'host=<host> user=<user> password=<test>' PUBLICATION testpub;
CREATE OR REPLACE FUNCTION notify_channel() RETURNS trigger AS $$
BEGIN
    RAISE LOG 'Notify Triggered';
    PERFORM pg_notify('testchannel', 'Testing');
    RETURN NEW;
END;
$$ LANGUAGE 'plpgsql';
DROP TRIGGER queue_insert ON TEST;
CREATE TRIGGER queue_insert AFTER INSERT ON test FOR EACH ROW EXECUTE PROCEDURE notify_channel();
ALTER TABLE test ENABLE ALWAYS TRIGGER queue_insert;
LISTEN testchannel;

--Execute insert on master:
INSERT INTO test (msg) VALUES ('test');

--Log from replica from postgresql-10-main.log:
--2018-07-24 07:45:15.705 EDT [6701] LOG:  00000: Notify Triggered
--2018-07-24 07:45:15.705 EDT [6701] CONTEXT:  PL/pgSQL function notify_channel() line 3 at RAISE
--2018-07-24 07:45:15.705 EDT [6701] LOCATION:  exec_stmt_raise, pl_exec.c:3337