src/main/java/com/theoryinpractise/halbuilder5/ResourceRepresentation.java
public ResourceRepresentation<V> withContent(ByteString content) {
    return new ResourceRepresentation<>(
        Option.of(content), links, rels, namespaceManager, value, resources);
  }
public ResourceRepresentation<V> withContent(ByteString content) {
    return new ResourceRepresentation<>(
        Option.of(content), links, rels, namespaceManager, value, resources);
  }
Adds or replaces the content of the representation.

@param content The source content of the representation.
@return A new instance of a PersistentRepresentation with the namespace included.