string getKey() Get the API key being used by the transport.

MailgunTransport class MailgunTransport extends

void registerPlugin(Swift_Events_EventListener $plugin) Register a plug-in

void registerPlugin(Swift_Events_EventListener $plugin) Register a plug-in

void __construct(LoggerInterface $logger) Create a new log transport instance

start() {@inheritdoc}

void __construct(ClientInterface $client, string $key, string $domain) Create

SparkPostTransport class SparkPostTransport extends

stop() {@inheritdoc}

isStarted() {@inheritdoc}