public function subscribe(Dispatcher $events)
{
$events->listen(DiskUsageHealthy::class, static::class . '@whenDiskUsageHealthy');
$events->listen(DiskUsageAlarm::class, static::class . '@whenDiskUsageAlarm');
$events->listen(HttpPingUp::class, static::class . '@whenHttpPingUp');
$events->listen(HttpPingDown::class, static::class . '@whenHttpPingDown');
$events->listen(SSLCertificateValid::class, static::class . '@whenSSLCertificateValid');
$events->listen(SSLCertificateInvalid::class, static::class . '@whenSSLCertificateInvalid');
$events->listen(SSLCertificateExpiring::class, static::class . '@whenSSLCertificateExpiring');
}