MapReduceFinishCommand both establishes cursors and merges them using ParallelSortClusteredCursor.

We should be able to replace the establishing cursors part with the new establishCursors() function, but I'm not sure what the best way to replace the merging functionality is.

My first thought is naturally to use the ARM, but currently the ARM is embedded in ClusterClientCursor, and ClusterClientCursor doesn't exist on shards.

david.storch, is there another way we might be able to merge the cursor streams on a shard (DocumentSourceMerge?)? Does the Query team still have plans to make the ARM available on shards?