TDAT:     protected void cleanup(ChannelHandlerContext ctx) {
        // Make sure we dispose everything on exit on session close
        SMTPSession smtpSession = (SMTPSession) ctx.getAttachment();

        if (smtpSession != null) {
            LifecycleUtil.dispose(smtpSession.getState().get(SMTPConstants.MAIL));
            LifecycleUtil.dispose(smtpSession.getState().get(SMTPConstants.DATA_MIMEMESSAGE_STREAMSOURCE));
        }

        super.cleanup(ctx);
    }
 COM: <s> cleanup temporary files </s>