@Override
    public boolean isDuplicate(Request request, Task task) {
        boolean isDuplicate = bloomFilter.mightContain(getUrl(request));
        if (!isDuplicate) {
            bloomFilter.put(getUrl(request));
            counter.incrementAndGet();
        }
        return isDuplicate;
    }
@param expectedInsertions the number of expected insertions to the constructed
@param fpp the desired false positive probability (must be positive and less than 1.0)
webmagic-extension/src/main/java/us/codecraft/webmagic/scheduler/BloomFilterDuplicateRemover.java