* - `'taskError'`: Emitted when an error occurs while executing a task.
* - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
*/
* - `'taskError'`: Emitted when an error occurs while executing a task.
* - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
*/