private static com.google.crypto.tink.proto.HmacPrfParams getProtoParams(
      HmacPrfParameters parameters) throws GeneralSecurityException {
    return com.google.crypto.tink.proto.HmacPrfParams.newBuilder()
        .setHash(toProtoHashType(parameters.getHashType()))
        .build();
  }
Methods to serialize and parse {@link HmacPrfKey} objects and {@link HmacPrfParameters} objects.
java_src/src/main/java/com/google/crypto/tink/prf/internal/HmacPrfProtoSerialization.java