code: function toCassandraValues(metadata, values) {
    if (values === null || values === undefined) {
      return null;
    }
    var specs = metadata.columnSpecs;
    var list = [];
    for (var i = 0; i < specs.length; i++) {
      var value = values[i];
      if (value === null || value === undefined) {
        list.push(null);
      } else {
        var spec = specs[i];
        var type = types.fromType(spec.type);
        list.push(type.serialize(value));
      }
    }
    return list;
  }
docs: Convert values to binaries to be set for cassandra
  @param {object} metadata - metadata
  @param {array} values - value list