@Override
  public void toData(DataOutput out,
      SerializationContext context) throws IOException {
    super.toData(out, context);
    out.writeLong(timestamp);
    out.writeInt(changeCount);
    for (int i = 0; i < changeCount; i++) {
      out.writeInt(listenerIds[i]);
      out.writeDouble(values[i]);
    }
  }
Notes that the value of a given statistics has changed
geode-core/src/main/java/org/apache/geode/internal/admin/remote/StatListenerMessage.java