code: func (options CollectionOptions) WithFallbackMarshalerUnmarshaler(fallback MarshalerUnmarshaler) CollectionOptions {
  	options.FallbackMarshalerUnmarshaler = fallback
  	return options
  }
docs: // WithFallbackMarshalerUnmarshaler returns a new copy of the options with the
  // FallbackMarshalerUnmarshaler property set to the given value. It does not
  // mutate the original options.