public static byte[] encode(byte[] input, int flags) {
    return encode(input, 0, input.length, flags);
  }
Base64-encode the given data and return a newly allocated byte[] with the result.

@param input the data to encode
@param flags controls certain features of the encoded output. Passing {@code DEFAULT} results
    in output that adheres to RFC 2045.
java_src/src/main/java/com/google/crypto/tink/subtle/Base64.java