code: public ToStringOption setUpToClass(Class<?> c) {
          ToStringOption op = this;
          if (this == DEFAULT_OPTION) {
              op = new ToStringOption(this.appendStatic, this.appendTransient);
          }
          op.upToClass = c;
          return op;
      }
docs: Return a <code>ToStringOption</code> instance with {@link #upToClass} option set.
  if the current instance is not {@link #DEFAULT_OPTION default instance} then set
  on the current instance and return the current instance. Otherwise, clone the default
  instance and set on the clone and return the clone
  
  @param c
  @return this option instance or clone if this is the {@link #DEFAULT_OPTION}