public static void startJweContent(OutputStream os,
JweHeaders headers,
JwtHeadersWriter writer,
byte[] encryptedContentEncryptionKey,
byte[] cipherInitVector) throws IOException {
writer = writer == null ? new JwtTokenReaderWriter() : writer;
byte[] jsonBytes = writer.headersToJson(headers).getBytes("UTF-8");
Base64UrlUtility.encodeAndStream(jsonBytes, 0, jsonBytes.length, os);
byte[] dotBytes = new byte[]{'.'};
os.write(dotBytes);
Base64UrlUtility.encodeAndStream(encryptedContentEncryptionKey, 0,