anchor.diff:    ///
     /// // Using privateKey Bob can sign a message for Alice.
     /// final message = 'Hi Alice';
  -  /// final signature = await keyPair.privateKey.sign(() async* {
  -  ///   yield utf8.encode(message);
  -  /// }());
  +  /// final signature = await keyPair.privateKey.sign(Stream.fromIterable([
  +  ///   utf8.encode(message),
  +  /// ]));
     ///
     /// // Given publicKey and signature Alice can verify the message from Bob.
     /// final isValid = await keypair.publicKey.verify(
     ///   signature,
  -  ///   () async* {
  -  ///     yield utf8.encode(message);
  -  ///   }(),
  +  ///   Stream.fromIterable([utf8.encode(message)]),
     /// );
     /// if (isValid) {
     ///   print('Authentic message from Bob: $message');
  
positive.code:   /// // Generate an HmacSecretKey.
    /// final key = await HmacSecretKey.generateKey(sha256);
    ///
    /// // Function that creates a stream of data from our string-to-sign:
    /// String stringToSign = 'example-string-to-signed';
    /// Stream<List<int>> dataStream() async* {
    ///   yield utf8.encode(stringToSign);
    /// }
    ///
    /// // Compute signature.
    /// final signature = await key.sign(dataStream());
    ///
    /// // Verify signature.
    /// final result = await key.verify(signature, dataStream());
    /// assert(result == true, 'this signature should be valid');
    /// ```
    Future<bool> verify(List<int> signature, Stream<List<int>> data);
  
negative.code:   /// import 'dart:convert' show base64, utf8;
    /// import 'package:webcrypto/webcrypto.dart';
    ///
    /// // Compute hash of 'hello world' with sha-256
    /// List<int> hash = await sha256.digest(
    ///   Stream.fromIterable([
    ///     // In this case our stream contains a single chunk of bytes.
  