Aerys\Server::doStart PHP Method

    private function doStart() : \Generator
    {
        assert($this->logDebug("starting"));
        $emitter = $this->makePrivateCallable("onParseEmit");
        $writer = $this->makePrivateCallable("writeResponse");
        $this->vhosts->setupHttpDrivers($emitter, $writer);
        $addrCtxMap = $this->generateBindableAddressContextMap();
        foreach ($addrCtxMap as $address => $context) {
            $this->boundServers[$address] = $this->bind($address, $context);
        }
        $this->state = self::STARTING;
        $notifyResult = (yield $this->notify());
        if ($hadErrors = (bool) $notifyResult[0]) {
            yield from $this->doStop();
            throw new \RuntimeException("Server::STARTING observer initialization failure");
        }
        /* enable direct access for performance, but Options now shouldn't be changed as Server has been STARTED */
        try {
            if (@\assert(false)) {
                $options = new class extends Options
                {
                    use \Amp\Struct;
                    private $_initialized = false;
                    public function __get(string $prop)
                    {
                        throw new \DomainException($this->generateStructPropertyError($prop));
                    }
                    public function __set(string $prop, $val)
                    {
                        if ($this->_initialized) {
                            throw new \RuntimeException("Cannot add options after server has STARTED.");
                        }
                        $this->{$prop} = $val;
                    }
                };
                foreach ((new \ReflectionObject($this->options))->getProperties() as $property) {
                    $name = $property->getName();
                    $options->{$name} = $this->options->{$name};
                }
                $this->options = $options;
            }
        } catch (\AssertionError $e) {
        }
        // lock options
        $this->options->_initialized = true;
        $this->dropPrivileges();
        $this->state = self::STARTED;
        assert($this->logDebug("started"));
        foreach ($this->boundServers as $serverName => $server) {
            $this->acceptWatcherIds[$serverName] = \Amp\onReadable($server, $this->onAcceptable);
            $this->logger->info("Listening on {$serverName}");
        }
        return $this->notify()->when(function ($e, $notifyResult) {
            if ($hadErrors = $e || $notifyResult[0]) {
                resolve($this->doStop())->when(function ($e) {
                    throw new \RuntimeException("Server::STARTED observer initialization failure", 0, $e);
                });
            }
        });
    }