description

# addEventListener method Null safety

void addEventListener (

1. String type,
2. EventListener? listener,
3. [bool? useCapture]

)
override

## Implementation

    void addEventListener(String type, EventListener? listener,
        [bool? useCapture]) {
      // Messages posted to ports are initially paused, allowing listeners to be
      // setup, start() needs to be explicitly invoked to begin handling messages.
      if (type == 'message') {
        _start();
      }

      super.addEventListener(type, listener, useCapture);
    }