public static HttpCacheEntry makeCacheEntry(final Instant requestDate, final Instant responseDate) {
        final Duration diff = Duration.between(requestDate, responseDate);
        final Instant when = requestDate.plusMillis(diff.toMillis() / 2);
        return makeCacheEntry(requestDate, responseDate, getStockHeaders(when));
    }
Generates a response body with random content.
 @param nbytes length of the desired response body
 @return an {@link HttpEntity}
httpclient5-cache/src/test/java/org/apache/hc/client5/http/impl/cache/HttpTestUtils.java