anchor.diff:  * Each sub-request gets a slightly different snapshot of the source index,
   though these are all taken at approximately the same time.
   
  -[float]
   [[docs-reindex-picking-slices]]
   ====== Picking the number of slices
   
  
positive.code: }
  ----------------------------------------------------------------
  
  [float]
  [[docs-reindex-automatic-slice]]
  ===== Automatic slicing
  
  You can also let `_reindex` automatically parallelize using <<sliced-scroll>> to
  slice on `_uid`. Use `slices` to specify the number of slices to use:
  
negative.code: <<docs-reindex-manual-slice, manual>> or
  <<docs-reindex-automatic-slice, automatic slicing>>.
  
  [[docs-reindex-manual-slice]]
  ====== Manual slicing
  Slice a reindex request manually by providing a slice id and total number of
  slices to each request:
  
  