public void write(KeysetWriter keysetWriter, Aead masterKey)
      throws GeneralSecurityException, IOException {
    writeWithAssociatedData(keysetWriter, masterKey, new byte[0]);
  }
Serializes, encrypts with {@code masterKey} and writes the keyset to {@code outputStream}.
java_src/src/main/java/com/google/crypto/tink/KeysetHandle.java