@CanIgnoreReturnValue
    public Builder withSharedPref(Context context, String keysetName, String prefFileName)
        throws IOException {
      if (context == null) {
        throw new IllegalArgumentException("need an Android context");
      }
      if (keysetName == null) {
        throw new IllegalArgumentException("need a keyset name");
      }
      this.context = context;
      this.keysetName = keysetName;
      this.prefFileName = prefFileName;

      return this;
    }
Reads and writes the keyset from shared preferences.
java_src/src/main/java/com/google/crypto/tink/integration/android/AndroidKeysetManager.java