private String getStringContent(MyHandler handler) {
        byte[] content = handler.content;
        return content == null ? null : StringSerializer.decode(content);
    }
@author <a href="mailto:zhanggeng.zg@antfin.com">GengZhang</a>
test/test-integration/src/test/java/com/alipay/sofa/rpc/transport/http/Http2ClearTextBadRequestTest.java