TaskStatusDone means task is done.

TaskStatusEnqueue means task is enqueued.

TaskStatusError means task error.

TaskStatusKilled means task is killed.

TaskStatusPoolClosed means task run worker pool closed.

TaskStatusQueueFull means task queue is full.

TaskStatusRunning means task is running.

TaskStatusTooManyWorker means task concurrence is greater then worker pool max worker count.

Pool is a buffered worker pool.

TaskResult is a manager of submitted task.

TaskStatus is the status of task.