function configure(name, value) {
  if (name === 'onerror') {
    // handle for legacy users that expect the actual
    // error to be passed to their function added via
    // `RSVP.configure('onerror', someFunctionHere);`
    config['on']('error', value);
    return;
  }

  if (arguments.length === 2) {
    config[name] = value;
  } else {
    return config[name];
  }
}
Use `trigger` to fire custom events. For example:
     ```javascript
    object.on('foo', function(){
      console.log('foo event happened!');
    });
    object.trigger('foo');
    // 'foo event happened!' logged to the console
    ```
     You can also pass a value as a second argument to `trigger` that will be
    passed as an argument to all event listeners for the event:
     ```javascript
    object.on('foo', function(value){
      console.log(value.name);
    });
     object.trigger('foo', { name: 'bar' });
    // 'bar' logged to the console
    ```
     @method trigger
    @for RSVP.EventTarget
    @private
    @param {String} eventName name of the event to be triggered
    @param {*} options optional value to be passed to any event handlers for
    the given `eventName`