code: public void updateTask(String jobId, String taskId, TaskConstraints constraints,
              Iterable<BatchClientBehavior> additionalBehaviors) throws BatchErrorException, IOException {
          TaskUpdateOptions options = new TaskUpdateOptions();
          BehaviorManager bhMgr = new BehaviorManager(this.customBehaviors(), additionalBehaviors);
          bhMgr.applyRequestBehaviors(options);
  
          this.parentBatchClient.protocolLayer().tasks().update(jobId, taskId, constraints, options);
      }
docs: Updates the specified task.
  
  @param jobId
  The ID of the job containing the task.
  @param taskId
  The ID of the task.
  @param constraints
  Constraints that apply to this task. If null, the task is given
  the default constraints.
  @param additionalBehaviors
  A collection of {@link BatchClientBehavior} instances that are
  applied to the Batch service request.
  @throws BatchErrorException
  Exception thrown when an error response is received from the
  Batch service.
  @throws IOException
  Exception thrown when there is an error in
  serialization/deserialization of data sent to/received from the
  Batch service.