@Deprecated
  public static HkdfPrfKey createPrfKey(byte[] keyValue) throws Exception {
    HkdfPrfParams params = HkdfPrfParams.newBuilder().setHash(HashType.SHA256).build();

    return HkdfPrfKey.newBuilder()
        .setParams(params)
        .setKeyValue(ByteString.copyFrom(keyValue))
        .build();
  }
@return a {@code HkdfPrfKey}.
@deprecated Do not use this function
java_src/src/main/java/com/google/crypto/tink/testing/TestUtil.java