private int estimateHitsToFetch(int wantedHits, int numPartitions) {
        return hitEstimator.estimateK(wantedHits, numPartitions);
    }
InterleavedSearchInvoker uses multiple {@link SearchInvoker} objects to interface with content
nodes in parallel. Operationally it first sends requests to all contained invokers and then
collects the results. The user of this class is responsible for merging the results if needed.

@author ollivir
container-search/src/main/java/com/yahoo/search/dispatch/InterleavedSearchInvoker.java