title: Configure Solr to reject index/update requests with later timestamp (in the document)
body: <p>While replaying documents (to cover for indexing holes), it is possible for my solr server to receive indexing reqests from two sources at the same time; and one of those sources will have an older copy of the document. I have <code>lastModified</code> timestamp in my solr documents. How can I use it to skip indexing the document if its recent copy has already been indexed (by the other stream)?</p>
  
  <p>I am considering to modify <code>UpdateHandler</code> and read the document before indexing (when more than one indexing 'streams' are in progress). I am not sure if this is a viable approach. </p>