public final Deserializer deserialize(Deserializer buf) {
        onDeserialize(buf);
        return buf;
    }
Deserializes the content (excluding the identifier) of this class from the given byte buffer. If you need the
identifier deserialized and verified, use the {@link #deserializeWithId(Deserializer)} method instead. This
method invokes the {@link #onDeserialize(Deserializer)} method.

@param buf The buffer to deserialize from.
@return The buffer argument, to allow chaining.
vespajlib/src/main/java/com/yahoo/vespa/objects/Identifiable.java