public function getHeader($header)
	{
		$n = ($header instanceof HttpHeaderInterface) ? strtolower($header->getFieldName()) : strtolower($header);
		
		if(!empty($this->headers[$n]))
		{
			return $this->headers[$n][0][1];
		}
		
		if(func_num_args() > 1)
		{
			return func_get_arg(1);
		}
		
		$name = ($header instanceof HttpHeaderInterface) ? $header->getFieldName() : $header;
		
		throw new \OutOfBoundsException(sprintf('HTTP header not found: "%s"', $name));
	}