title: How to stop threads created by org.asynchttpclient to prevent memory leak?
body: <p>I am using org.asynchttpclient to post async request.</p>
  
  <p>While shutting down tomcat, I am getting below logs:</p>
  
  <blockquote>
    <p>SEVERE: The web application [/test] appears to have started a thread named [pool-1-thread-1] but has failed to stop it. This is very likely to create a memory leak.<br>
    Jul 04, 2017 10:53:00 AM org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads</p>
    
    <p>SEVERE: The web application [/test] appears to have started a thread named [AsyncHttpClient-2-1] but has failed to stop it. This is very likely to create a memory leak.<br>
    Jul 04, 2017 10:53:00 AM org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads</p>
    
    <p>SEVERE: The web application [/test] appears to have started a thread named [AsyncHttpClient-2-2] but has failed to stop it. This is very likely to create a memory leak.<br>
    Jul 04, 2017 10:53:00 AM org.apache.catalina.loader.WebappClassLoaderBase checkThreadLocalMapForLeaks</p>
    
    <p>SEVERE: The web application [/test] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@71513074]) and a value of type [io.netty.util.internal.InternalThreadLocalMap] (value [io.netty.util.internal.InternalThreadLocalMap@4aecc2e8]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.</p>
  </blockquote>
  
  <p>How to close these threads to prevent memory leak. </p>