Documented event listeners / callbacks not implemented?

[joostthehost]

According to the docs, there should be a bunch of Event Handlers. However, when trying to implement any one of those, it appears like they just aren't implemented?

Configuration in docs. The event listeners are reported at the end of the config section.

/**
   * EVENT LISTENERS:
   *
   * Callback function for when a sort operation is performed.
   */  
onSort?: SortEvent;

  /**
   * Callback function for when a transfer operation is performed.
   */  
onTransfer?: TransferEvent;

  /**
   * Fired when a drag is started, whether native drag or synthetic
   */  
onDragstart?: DragstartEvent;

  /**
   * Fired when a drag is ended, whether native drag or synthetic
   */  
onDragend?: DragendEvent;