anchor.diff:     * [EventSink] that allows putting events into the returned stream.
      * This `EventSink` is only valid during the call to [onTimeout].
      * Calling [EventSink.close] on the sink passed to [onTimeout] closes the
  -   * returned stream, and no futher events are processed.
  +   * returned stream, and no further events are processed.
      *
      * If [onTimeout] is omitted, a timeout will just put a [TimeoutException]
      * into the error channel of the returned stream.
  
positive.code:       _StreamBindTransformer<S, T>;
  
    /**
     * Adapts [source] to be a `StreamTransfomer<TS, TT>`.
     *
     * This allows [source] to be used at the new type, but at run-time it
     * must satisfy the requirements of both the new type and its original type.
  
negative.code:    * The iterable is iterated when the stream receives a listener, and stops
     * iterating if the listener cancels the subscription, or if the
     * [Iterator.moveNext] method returns `false` or throws.
     * Iteration is suspended while the stream subscription is paused.
     *
     * If calling [Iterator.moveNext] on `elements.iterator` throws,
     * the stream emits that error and then it closes.
  