private HttpStatus httpStatus() {
        return status == null ? !contentStream.hasFlushed() &&
                                !contentStream.hasWritten() ? HttpStatus.NO_CONTENT
                                                            : HttpStatus.OK
                              : status;
    }
Implements {@link org.jboss.resteasy.spi.HttpResponse}.
resteasy/src/main/java/com/linecorp/armeria/server/resteasy/ResteasyHttpResponseImpl.java