http://nexus.sonatype.org/oss-repository-hosting.html/vertx-parent/vertx-ext/vertx-ext-parent/vertx-mqtt: Vert.x MQTT reactive client and server (Eclipse) 
public interface io.vertx.mqtt.MqttTopicSubscription
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: io.vertx.mqtt.MqttTopicSubscription
  super_class: java.lang.Object
{
  public abstract java.lang.String topicName();
    descriptor: ()Ljava/lang/String;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    RuntimeVisibleAnnotations: 
      io.vertx.codegen.annotations.CacheReturn()

  public abstract io.netty.handler.codec.mqtt.MqttQoS qualityOfService();
    descriptor: ()Lio/netty/handler/codec/mqtt/MqttQoS;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    RuntimeVisibleAnnotations: 
      io.vertx.codegen.annotations.CacheReturn()
}
SourceFile: "MqttTopicSubscription.java"
    RuntimeVisibleAnnotations: 
      io.vertx.codegen.annotations.VertxGen()