@Override
                public Integer apply(String key) {
                  return multiset.count(key);
                }
              });
      assertEquals("Counts not as expected", Ints.asList(deltas), actualCounts);
    } finally {
      pool.shutdownNow();
    }

    // Since we have access to the backing map, verify that there are no zeroes in the map

                @Override
                public Integer apply(String key) {
                  return multiset.count(key);
                }
              });
      assertEquals("Counts not as expected", Ints.asList(deltas), actualCounts);
    } finally {
      pool.shutdownNow();
    }

    // Since we have access to the backing map, verify that there are no zeroes in the map