private boolean isInDataSet(Object key, Object callbackArgument) {
    Integer bucketIdInt = getHashKey(Operation.CONTAINS_KEY, key, null, callbackArgument);
    return buckets.contains(bucketIdInt);
  }
This instance method was added so that unit tests could mock it
geode-core/src/main/java/org/apache/geode/internal/cache/LocalDataSet.java