class_docstr: Message sent from a worker to the pool to notify the pool about completed tasks
  along with meta data needed to fetch and deserialize results stored in the shared memory
  
  Parameters
  ----------
  `worker_id` : int
      Id of the worker that completed the task.
  `context_i` : int
      Index identifying the callback in the order of parallel callbacks passed to pool.
  `scheduled_i` : int
      Ordinal of the batch that tasks corresponds to.
  `minibatch_i` : int
      Computation of batch might be split into number of minibatches, this is the number
      that identifies which consecutive part of the batch it is.
  `batch_meta` :  nvidia.dali._multiproc.shared_batch.SharedBatchMeta
      Serialized result of the task.
  `exception`
      Exception if the task failed.
code: def __init__(
      self,
      worker_id,
      context_i,
      scheduled_i,
      minibatch_i,
      batch_meta=None,
      exception=None,
      traceback_str=None,
  ):
      self.worker_id = worker_id
      self.context_i = context_i
      self.scheduled_i = scheduled_i
      self.minibatch_i = minibatch_i
      self.batch_meta = batch_meta
      self.exception = exception
      self.traceback_str = traceback_str
  
imports: from typing import Optional
  from nvidia.dali.types import SampleInfo
  from nvidia.dali._multiproc.struct_message import Structure
label_desc: Use image node_id 1 to create a new CompletedTask object  with example: obj = CompletedTask(worker_id, context_i, scheduled_i, minibatch_i, batch_meta, exception, traceback_str)