protons-runtime 5.x is 2x slower than protons-runtime 3.x

This is the proto file https://github.com/ChainSafe/js-libp2p-gossipsub/blob/v10.0.0/src/message/rpc.proto

This is the testing code https://github.com/ChainSafe/js-libp2p-gossipsub/blob/v10.0.0/test/benchmark/protobuf.test.ts

With `protons-runtime` v3 I got:

```
protobuf
✔ decode Attestation message 3446018 ops/s 290.1900 ns/op - 2053201 runs 60.1 s
✔ encode Attestation message 2506831 ops/s 398.9100 ns/op - 1492091 runs 60.0 s
```

with `protons-runtime` v5 I got:

```
protobuf
✔ decode Attestation message using protons 5.1.0 1645793 ops/s 607.6100 ns/op - 983127 runs 60.1 s
✔ encode Attestation message using protons 5.1.0 1630497 ops/s 613.3100 ns/op - 972079 runs 60.0 s
```