static byte[] labelInfo(String label, byte[] info, byte[] suiteId, int length)
      throws GeneralSecurityException {
    return Bytes.concat(intToByteArray(2, length), HPKE_V1, suiteId, label.getBytes(UTF_8), info);
  }
Transforms {@code info} into labeled info using {@code label}, {@code suiteId}, and {@code
length} according to {@code LabeledExpand()} defined in
https://www.rfc-editor.org/rfc/rfc9180.html#section-4.

@throws GeneralSecurityException when byte concatenation fails.
java_src/src/main/java/com/google/crypto/tink/hybrid/internal/HpkeUtil.java