public void close() {
        if (writer != null && count > 0) {
            flush();
        }
        if (buf.length <= BUFFER_THRESHOLD) {
            bufLocal.set(buf);
        }

        this.buf = null;
    }
Close the stream. This method does not release the buffer, since its contents might still be required. Note:
Invoking this method in this class will have no effect.
src/main/java/com/alibaba/fastjson/serializer/SerializeWriter.java