FieldDescriptor primitiveField =
messageType.findFieldByName("optional_int32");
FieldDescriptor enumField =
messageType.findFieldByName("optional_nested_enum");
FieldDescriptor messageField =
messageType.findFieldByName("optional_foreign_message");
FieldDescriptor cordField =
messageType.findFieldByName("optional_cord");
FieldDescriptor extension =
UnittestProto.optionalInt32Extension.getDescriptor();
FieldDescriptor nestedExtension = TestRequired.single.getDescriptor();