@Override
  public int hashCode() {
    return key.hashCode();
  }
@Test
  public void hashcode_uses_only_key() {
    int expected = new MetricImpl(SOME_UUID, SOME_KEY, SOME_NAME, Metric.MetricType.FLOAT).hashCode();

    assertThat(new MetricImpl(SOME_UUID, SOME_KEY, "some other name", Metric.MetricType.FLOAT).hashCode()).isEqualTo(expected);
    assertThat(new MetricImpl(SOME_UUID, SOME_KEY, "some other name", Metric.MetricType.BOOL).hashCode()).isEqualTo(expected);
  }