static int calculateHashMapCapacity(int numMappings) {
    return (int) Math.ceil(numMappings / DEFAULT_LOAD_FACTOR);
  }
@Test
  public void calculateHashMapCapacity() {
    @SuppressWarnings("UnnecessaryMethodReference")
    Iterable<Integer> iterable = List.of(1, 2, 3)::iterator;
    assertThat(Caffeine.calculateHashMapCapacity(iterable)).isEqualTo(16);
    assertThat(Caffeine.calculateHashMapCapacity(List.of(1, 2, 3))).isEqualTo(4);
  }