   #         pending_tasks: 0 }
   #
   # If there're no finished tasks, `average_pending_time` and
-  # `average_processing_time` will both be string `-`.
+  # `average_process_time` will both be string `-`.
   #
   # **Usage:**
   #


      # Calculate blocked and pending tasks:
      # 
      #   1. Set `blocked.groups` of result.
      #   2. Initiate another transaction to count all `BLOCKED` tasks. Blocked
      #   tasks are tasks in the `QUEUED` lists whose group identifiers are in
      #   the `BLOCKED` set. **Note:** The leftmost task of each `QUEUED` list
      #   will not be counted, since that's the causing (failed) task.
      #   3. Calculate pending tasks.
      #
      # The equation used to calculate pending tasks is:
      #
      #      pending = total - finished - processing - failed - blocked
      result.blocked.groups = multi_res[4].length
      multi2 = @redis.multi()
      multi2.llen "#{@key('QUEUED')}:#{group}" for group in multi_res[4]
      multi2.exec (multi2_err, multi2_res) ->


      # Process the result of the transaction.
      #
      # + Assign multi results to result object, and:
      # + Convert:
      #   - `total_pending_time` into `average_pending_time`, and:
      #   - `total_process_time` into `average_process_time`
      # + Calibrate initial condition (in case of no task is finished).
      statistics = multi_res[1] or {}
      result =
        name: @name
