public function __clone()
{
$this->headers = clone $this->headers;
$this->encoder = clone $this->encoder;
$this->cacheKey = md5(uniqid(getmypid() . mt_rand(), true));
$children = array();
foreach ($this->children as $pos => $child) {
$children[$pos] = clone $child;
}
$this->setChildren($children);
}