@Test
  public void parseParameters_outputPrefixIgnored_legacy() throws Exception {
    AesGcmHkdfStreamingParameters parameters =
        AesGcmHkdfStreamingParameters.builder()
            .setKeySizeBytes(37)
            .setDerivedAesGcmKeySizeBytes(32)
            .setHkdfHashType(AesGcmHkdfStreamingParameters.HashType.SHA512)
            .setCiphertextSegmentSizeBytes(512 * 1024)
            .build();

    ProtoParametersSerialization serialization =
        ProtoParametersSerialization.create(
            TYPE_URL,
            OutputPrefixType.LEGACY,
            com.google.crypto.tink.proto.AesGcmHkdfStreamingKeyFormat.newBuilder()
                .setKeySize(37)
                .setParams(
                    com.google.crypto.tink.proto.AesGcmHkdfStreamingParams.newBuilder()
                        .setCiphertextSegmentSize(512 * 1024)
                        .setDerivedKeySize(32)
                        .setHkdfHashType(HashType.SHA512))
                .build());

    Parameters parsed = registry.parseParameters(serialization);
    assertThat(parsed).isEqualTo(parameters);
  }
Test that if "OutputPrefixType" is set to CRUNCHY, we just ignore it.
java_src/src/test/java/com/google/crypto/tink/streamingaead/internal/AesGcmHkdfStreamingProtoSerializationTest.java