Subscribe to a message. topic: Name of the message to subscribe to. callback: Function to invoke when the message is published.
Subscribe to a message. topic: Name of the message to subscribe to. context: What this will be when the callback is invoked. callback: Function to invoke when the message is published. [priority]: Priority relative to other subscriptions for the same message. Lower values have higher priority. Default is 10.
Subscribe to a message. topic: Name of the message to subscribe to. callback: Function to invoke when the message is published. [priority]: Priority relative to other subscriptions for the same message. Lower values have higher priority. Default is 10.