code: private void writeObject(ObjectOutputStream out) throws IOException {
          Storable s = mStorable;
          if (s == null) {
              out.write(0);
          } else {
              out.write(1);
              out.writeObject(s.storableType());
              try {
                  s.writeTo(out);
              } catch (SupportException e) {
                  throw new IOException(e);
              }
          }
      }
docs: server is identical. Linking into the actual repository is a bit trickier.