protected static HpkeSpi findSpi(String algorithm) throws NoSuchAlgorithmException {
    if (algorithm == null) {
      // Same behaviour as Cipher.getInstance
      throw new NoSuchAlgorithmException("null algorithm");
    }
    return findSpi(algorithm, findFirstProvider(algorithm));
  }
Returns the {@link HpkeSpi} being used by this HpkeContext.

@return the SPI
common/src/main/java/org/conscrypt/HpkeContext.java