A report merger that generates a merged report defined as follows:
The start time is the minimum of start times
The end time is the maximum of end times
The total read records is the sum of total read records
The total written records is the sum of total written records
The total filtered records is the sum of total filtered records
The total error records is the sum of total error records
The final status is
JobStatus.COMPLETED
(if all partials are completed) or
JobStatus.FAILED
(if one of partials has failed).
The final name is the concatenation of partial job names.