parameters: (self, topic_name, qos_profile, event_callbacks, defer_subscribe=False)
docstring: Create a Listener.
  
          @param topic_name Topic to subscribe to.
          @param qos_profile QoS profile for Subscription.
          @param event_callbacks QoS event callbacks for Subscription.
          @param defer_subscribe Don't create Subscription until user calls start_listening()
docstring_summary: Create a Listener.
docstring_tokens: Create a Listener .
function: def __init__(self, topic_name, qos_profile, event_callbacks, defer_subscribe=False):
          """
          Create a Listener.
  
          @param topic_name Topic to subscribe to.
          @param qos_profile QoS profile for Subscription.
          @param event_callbacks QoS event callbacks for Subscription.
          @param defer_subscribe Don't create Subscription until user calls start_listening()
          """
          super().__init__('qos_listener')
          self.subscription = None
          self.topic_name = topic_name
          self.qos_profile = qos_profile
          self.event_callbacks = event_callbacks
          if not defer_subscribe:
              self.start_listening()
function_tokens: def __init__ ( self , topic_name , qos_profile , event_callbacks , defer_subscribe = False ) : super ( ) . __init__ ( 'qos_listener' ) self . subscription = None self . topic_name = topic_name self . qos_profile = qos_profile self . event_callbacks = event_callbacks if not defer_subscribe : self . start_listening ( )