@Override
    public void fromData(DataInput in,
        DeserializationContext context) throws IOException, ClassNotFoundException {
      super.fromData(in, context);
      isPrimary = in.readBoolean();
    }
The reply to a PrimarRequestMessage, indicating if the sender is the primary
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/PrimaryRequestMessage.java