@Override
  public byte[] labeledExpand(byte[] prk, byte[] info, String infoLabel, byte[] suiteId, int length)
      throws GeneralSecurityException {
    return expand(prk, HpkeUtil.labelInfo(infoLabel, info, suiteId, length), length);
  }
Copied from {@link com.google.crypto.tink.subtle.Hkdf#computeHkdf(String, byte[], byte[],
byte[], int)}
java_src/src/main/java/com/google/crypto/tink/hybrid/internal/HkdfHpkeKdf.java