public ClientCacheFactory setPoolIdleTimeout(long idleTimeout) {
    getPoolFactory().setIdleTimeout(idleTimeout);
    return this;
  }
Set the amount of time a connection can be idle before expiring the connection. If the pool
size is greater than the minimum specified by {@link #setPoolMinConnections(int)}, connections
which have been idle for longer than the idleTimeout will be closed.

@param idleTimeout The amount of time in milliseconds that an idle connection should live
       before expiring. -1 indicates that connections should never expire.
@return a reference to <code>this</code>
@throws IllegalArgumentException if <code>idleTimout</code> is less than <code>-1</code>.
geode-core/src/main/java/org/apache/geode/cache/client/ClientCacheFactory.java