anchor.diff:  GET /twitter/_stats/commit?level=shards
   --------------------------------------------------
   // AUTOSENSE
  +
  +
  +which returns something similar to:
  +
  +[source,js]
  +--------------------------------------------------
  +{
  +   ...
  +   "indices": {
  +      "twitter": {
  +         "primaries": {},
  +         "total": {},
  +         "shards": {
  +            "0": [
  +               {
  +                  "routing": {
  +                     ...
  +                  },
  +                  "commit": {
  +                     "id": "te7zF7C4UsirqvL6jp/vUg==",
  +                     "generation": 2,
  +                     "user_data": {
  +                        "sync_id": "AU2VU0meX-VX2aNbEUsD" <1>,
  +                        ...
  +                     },
  +                     "num_docs": 0
  +                  }
  +               }
  +               ...
  +            ],
  +            ...
  +         }
  +      }
  +   }
  +}
  +--------------------------------------------------
  +<1> the `sync id` marker
   
   [float]
   === Synced Flush API
   
   The Synced Flush API allows an administrator to initiate a synced flush manually. This can be particularly useful for
  -a planned (rolling) cluster restart where one can stop indexing and doesn't want to wait for the default 30 minutes to pass
  -when the synced flush will be performed automatically.
  +a planned (rolling) cluster restart where you can stop indexing and don't want to wait the default 30 minutes for
  +idle indices to be sync-flushed automatically.
   
   While handy, there are a couple of caveats for this API:
   
   1. Synced flush is a best effort operation. Any ongoing indexing operations will cause
  -the synced flush to fail. This means that some shards may be synced flushed while others aren't. See below for more.
  +the synced flush to fail on that shard. This means that some shards may be synced flushed while others aren't. See below for more.
   2. The `sync_id` marker is removed as soon as the shard is flushed again. That is because a flush replaces the low level
   lucene commit point where the marker is stored. Uncommitted operations in the transaction log do not remove the marker.
   In practice, one should consider any indexing operation on an index as removing the marker as a flush can be triggered by Elasticsearch
   at any time.
  +
  +
  +NOTE: It is harmless to request a synced flush while there is ongoing indexing. Shards that are idle will succeed and shards
  + that are not will fail. Any shards that succeeded will have faster recovery times.
   
   
   [source,bash]
  
positive.code: }
  --------------------------------------------------
  
  
  Sometimes the failures are specific to a shard copy. The copies that failed will not be eligible for
  fast recovery but those that succeeded still will be. This case is reported as follows:
  
negative.code: --------------------------------------------------
  
  
  NOTE: When a shard copy fails to sync-flush, the HTTP status code returned will be `409 CONFLICT`.
  
  The synced flush API can be applied to more than one index with a single call,
  or even on `_all` the indices.
  
  