static gboolean compare_by_coherent_set_key(gconstpointer key_a, gconstpointer key_b) {
  return memcmp(key_a, key_b, sizeof(coherent_set_key)) == 0;
}
static gboolean compare_by_coherent_set_key(gconstpointer key_a, gconstpointer key_b) {
  return memcmp(key_a, key_b, sizeof(coherent_set_key)) == 0;
}