StructUnion {  option (gogoproto.onlyone) = true;  optional double Field0 = 0;  optional float Field0 = 0;  optional NidOptNative Field0 = 0;  optional NinOptNative Field0 = 0;  optional uint00 Field0 = 0;  optional sint00 Field0 = 0;  optional bool Field00 = 00;  optional string Field00 = 00;  optional bytes Field00 = 00; }  message NinEmbeddedStructUnion {  option (gogoproto.onlyone) = true;  optional NidOptNative Field0 = 0 [(gogoproto.embed) = true];  optional NinOptNative Field000 = 000;  optional bool Field000 = 000; }  message Ni