whichOneofField method
Implementation
TestHugeFieldNumbersLite_OneofField whichOneofField() =>
_TestHugeFieldNumbersLite_OneofFieldByTag[$_whichOneof(0)]!;
TestHugeFieldNumbersLite_OneofField whichOneofField() =>
_TestHugeFieldNumbersLite_OneofFieldByTag[$_whichOneof(0)]!;