anchor.diff:      queue_size of `1000`.
   
   `analyze`::
  -    For analyze requests. Thread pool type is `fixed` with a size of 1, queue size of 16.
  +    For analyze requests. Thread pool type is `fixed` with a size of `1`, queue 
  +    size of `16`.
   
   `write`::
       For single-document index/delete/update and bulk requests. Thread pool type
  
positive.code:     keep-alive of `5m` and a max of `min(10, (# of available processors)/2)`.
  
  `listener`::
      Mainly for java client executing of action when listener threaded is set to true.
      Thread pool type is `scaling` with a default max of `min(10, (# of available processors)/2)`.
  
  `fetch_shard_started`::
      For listing shard states.
  
negative.code: requests with a queue (optionally bounded) for pending requests that
  have no threads to service them.
  
  The `size` parameter controls the number of threads.
  
  The `queue_size` allows to control the size of the queue of pending
  requests that have no threads to execute them. By default, it is set to
  