Airship\Engine\Keyggdrasil::fetchTreeUpdates PHP Method

    protected function fetchTreeUpdates(Channel $chan, string $url, string $root) : array
    {
        try {
            return $this->parseTreeUpdateResponse($chan, $this->hail->getSignedJSON($url . API::get('fetch_keys') . '/' . $root, $chan->getPublicKey()));
        } catch (SignatureFailed $ex) {
            $state = State::instance();
            if (IDE_HACKS) {
                $state->logger = new Ledger();
            }
            $state->logger->alert('Signature failed!', \Airship\throwableToArray($ex));
        }
        return [];
    }