anchor.diff:     * 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 the stream after the first matching element or error
  +   * 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
  
positive.code:   /**
     * Collects the data of this stream in a [Set].
     *
     * Creates a `Set<T>` and adds all elements of the stream to the set.
     * in the order they arrive.
     * When the stream ends, the returned future is completed with that set.
     *
     * The returned set is the same type as returned by `new Set<T>()`.
     * If another type of set is needed, either use [forEach] to add each
  
negative.code:    *
     * If the error is intercepted, the [onError] function can decide what to do
     * with it. It can throw if it wants to raise a new (or the same) error,
     * or simply return to make this stream forget the error.
     * If the received `error` value is thrown again by the [onError] function,
     * it acts like a `rethrow` and it is emitted along with its original
     * stack trace, not the stack trace of the `throw` inside [onError].
  