title: search_after with spring-data-elasticsearch
body: <p>Has anyone successfully used search_after with spring-data-elasticsearch?</p>
  
  <p>I've added _uid to my sort which is correctly getting put in my Pageable by the @Controller.  I turned on the slow query log and validated if I manually run the query the @Repository generates,  I get in the response:</p>
  
  <pre><code>    "sort": [
        1522270372773,
        "log#AWJuYn7SAKReCIGzMYda"
      ]
  </code></pre>
  
  <p>I added into my pojo (the class returned by the @Repository):</p>
  
  <pre><code> @JsonProperty("sort")
   String[] sort;
  </code></pre>
  
  <p>Sort is always coming back as null.    Tried a couple different things and cannot figure out how to get sort to be set.   Any ideas?</p>