public MqttClientService(
     ILogger <MqttClientService> logger,
     IMqttClientServiceOptions serviceOptions,
     IMqttClientOptions clientOptions)
 {
     _logger         = logger ?? throw new ArgumentNullException(nameof(logger));
     _clientOptions  = clientOptions ?? throw new ArgumentNullException(nameof(clientOptions));
     _serviceOptions = serviceOptions ?? throw new ArgumentNullException(nameof(serviceOptions));
 }
 public MqttSubscriberService(
     EmailProcessor processor,
     ILogger <MqttSubscriberService> logger,
     IMqttClientServiceOptions serviceOptions,
     IMqttClientOptions clientOptions)
 {
     _processor      = processor ?? throw new ArgumentNullException(nameof(processor));
     _logger         = logger ?? throw new ArgumentNullException(nameof(logger));
     _clientOptions  = clientOptions ?? throw new ArgumentNullException(nameof(clientOptions));
     _serviceOptions = serviceOptions ?? throw new ArgumentNullException(nameof(serviceOptions));
 }