title: What's the trigger condition of Transfer-Encoding: chunked for Tomcat 8
body: <p>Here is the configuration in the <code>server.xml</code> in my tomcat 8.</p>
  
  <pre><code>&lt;Connector port="8080" protocol="HTTP/1.1"
             connectionTimeout="20000"
             redirectPort="8443" /&gt;
  </code></pre>
  
  <p>and I just find that some RESTful api requests return with <code>Transfer-Encoding: chunked</code> header, some are not. And looks it's not following the rule that I understood before: "the response that content size exceeds a threshold (say 8k) will return with <code>Transfer-Encoding: chunked</code>"</p>
  
  <p>so my question is that what is the exactly trigger condition of <code>Transfer-Encoding: chunked</code></p>