anchor.diff:    /// ```
     ///
     /// [1]: https://chromium.googlesource.com/chromium/src/+/43d62c50b705f88c67b14539e91fd8fd017f70c4/components/webcrypto/algorithms/rsa.cc#286
  -  static Future<
  -          CryptoKeyPair<RsassaPkcs1V15PrivateKey, RsassaPkcs1V15PublicKey>>
  +  static Future<KeyPair<RsassaPkcs1V15PrivateKey, RsassaPkcs1V15PublicKey>>
         generateKey(int modulusLength, BigInt publicExponent, Hasher hasher) {
       ArgumentError.checkNotNull(modulusLength, 'modulusLength');
       ArgumentError.checkNotNull(publicExponent, 'publicExponent');
  
positive.code:     throw UnimplementedError('TODO: implement RSA-PSS');
    }
  
    static Future<CryptoKeyPair<RsaPssPrivateKey, RsaPssPublicKey>> generateKey(
      int modulusLength,
      BigInt publicExponent,
      Hasher hasher,
  
negative.code:     throw UnimplementedError('TODO: implement RSA-OAEP');
    }
  
    static Future<KeyPair<RsaOaepPrivateKey, RsaPssPublicKey>> generateKey(
      int modulusLength,
      BigInt publicExponent,
      Hasher hasher,
  