title: How to control error handling and synchronization in Antlr 4 / c#
body: <p>I'm using Antlr 4 with c# target.
  Here is a subset of my grammar:</p>
  
  <pre><code>/*
   * Parser Rules
   */
  text : term+  EOF;
  term : a1 a2 a3;
  a1: ....
  ...
  ...
  </code></pre>
  
  <p>I want to accept valid data blocks as (term)s, when error exists I want to search for the next valid term and print out the whole text which caused the error for user to analyze manually.</p>
  
  <p>How to synchronize input to the next valid term? 
  and How to get the ignored text?</p>