@CanIgnoreReturnValue
  public synchronized AndroidKeysetManager enable(int keyId) throws GeneralSecurityException {
    keysetManager = keysetManager.enable(keyId);
    write(keysetManager.getKeysetHandle(), writer, masterAead);
    return this;
  }
Enables the key with {@code keyId}.

@throws GeneralSecurityException if the key is not found
java_src/src/main/java/com/google/crypto/tink/integration/android/AndroidKeysetManager.java