@Override
  public int compareTo(V1Annotation that) {
    if (this == that) return 0;
    int byTimestamp = timestamp < that.timestamp ? -1 : timestamp == that.timestamp ? 0 : 1;
    if (byTimestamp != 0) return byTimestamp;
    return value.compareTo(that.value);
  }
Compares by {@link #timestamp()}, then {@link #value()}.
zipkin/src/main/java/zipkin2/v1/V1Annotation.java