public MessageDescriptorBuilder <T> Fixed64PackedArray(int fieldNum, Func <T, IEnumerable <ulong> > valueGetter, Action <T, ulong> oneValueSetter, Func <T, bool> hasValueFunc = null, bool canReadUnpacked = true)
 {
     return(Add(FieldSetting <T> .CreateFixed64PackedArray(fieldNum, valueGetter, oneValueSetter, hasValueFunc, canReadUnpacked)));
 }