anchor.diff:     * by the [onError] function.
      *
      * The [onError] callback must be of type `void onError(error)` or
  -   * `void onError(error, StackTrace stackTrace)`. Depending on the function
  -   * type the stream either invokes [onError] with or without a stack
  -   * trace. The stack trace argument might be `null` if the stream itself
  -   * received an error without stack trace.
  +   * `void onError(error, StackTrace stackTrace)`.
  +   * The function type determines whether [onError] is invoked with a stack
  +   * trace argument.
  +   * The stack trace argument may be `null` if this stream received an error
  +   * without a stack trace.
      *
      * An asynchronous error `error` is matched by a test function if
      *`test(error)` returns true. If [test] is omitted, every error is considered
  
positive.code:    * The `streamConsumer` is closed when this stream has been successfully added
     * to it - when the future returned by `addStream` completes without an error.
     *
     * Returns a future which completes when the stream has been consumed
     * and the consumer has been closed.
     *
     * The returned future completes with the same result as the future returned
  
negative.code:    * If this stream emits an error before the first matching element,
     * the returned future is completed with that error, and processing stops.
     *
     * Stops listening to this stream after the first matching element or error
     * has been received.
     *
     * Internally the method cancels its subscription after the first element that
  