anchor.diff:  // TEST[s/"password": "pass"//]
   
   The `host` parameter must contain a scheme, host, port (e.g.
  -`https://otherhost:9200`) and optional path (e.g. `https://otherhost:9200/proxy`).
  +`https://otherhost:9200`), and optional path (e.g. `https://otherhost:9200/proxy`).
   The `username` and `password` parameters are optional, and when they are present `_reindex`
   will connect to the remote Elasticsearch node using basic auth. Be sure to use `https` when
   using basic auth or the password will be sent in plain text.
  
positive.code: 
  In addition to the standard parameters like `pretty`, the Reindex API also
  supports `refresh`, `wait_for_completion`, `wait_for_active_shards`, `timeout`,
  `scroll` and `requests_per_second`.
  
  Sending the `refresh` url parameter will cause all indexes to which the request
  wrote to be refreshed. This is different than the Index API's `refresh`
  
negative.code: are distributed proportionally to each sub-request. Combine that with the point
  above about distribution being uneven and you should conclude that the using
  `size` with `slices` might not result in exactly `size` documents being
  reindexed.
  * Each sub-request gets a slightly different snapshot of the source index,
  though these are all taken at approximately the same time.
  
  