@JsonCreator
    @SuppressWarnings("unused")
    public static LookupCacheKey createFromJSON(@JsonProperty("prefix") String prefix, @JsonProperty("key") @Nullable Object key) {
        return new AutoValue_LookupCacheKey(prefix, key);
    }
@Test
    public void serialize() {
        final LookupCacheKey cacheKey = LookupCacheKey.createFromJSON("prefix", "key");
        final JsonNode node = objectMapper.convertValue(cacheKey, JsonNode.class);
        assertThat(node.isObject()).isTrue();
        assertThat(node.fieldNames()).toIterable().containsExactlyInAnyOrder("prefix", "key");
        assertThat(node.path("prefix").isTextual()).isTrue();
        assertThat(node.path("prefix").asText()).isEqualTo("prefix");
        assertThat(node.path("key").isTextual()).isTrue();
        assertThat(node.path("key").asText()).isEqualTo("key");
    }