@Override
    public Authenticator authenticate(Vertx vertx, Map<String, String> config, MultiMap headerMap, Handler<AsyncResult<Void>> resultHandler) {
        headerMap.set("Authorization", Basic.encode(config.get("username"), config.get("password")));
        resultHandler.handle(Future.succeededFuture());
        return this;
    }
Set BASIC auth credentials.

<ul>
  <li>username: username</li>
  <li>password: password</li>
</ul>

@author Marc Savy {@literal <marc@rhymewithgravy.com>}
gateway/engine/vertx-polling/src/main/java/io/apiman/gateway/engine/vertx/polling/fetchers/auth/BasicAuth.java