code: @BetaApi
    public static FieldValueList of(List<FieldValue> row, FieldList schema) {
      return new FieldValueList(row, schema);
    }
docs: Creates an instance of {@code FieldValueList}, useful for testing.
  
  <p>This method is unstable. See <a
  href="https://github.com/googleapis/google-cloud-java/pull/2891">this discussion</a> for more
  context.