function cloneSet(set, isDeep, cloneFunc) {
  var array = isDeep ? cloneFunc(setToArray(set), CLONE_DEEP_FLAG) : setToArray(set);
  return arrayReduce(array, addSetEntry, new set.constructor());
}
Creates a clone of `set`.

@private
@param {Object} set The set to clone.
@param {Function} cloneFunc The function to clone values.
@param {boolean} [isDeep] Specify a deep clone.
@returns {Object} Returns the cloned set.