))
        @throwTypeError("ReadableStreamDefaultController needs a ReadableStream");

    //
    if (@getByIdDirectPrivate(stream, "readableStreamController") !== null)
        @throwTypeError("ReadableStream already has a controller");

    @putByIdDirectPrivate(this, "controlledReadableStream", stream);
    @putByIdDirectPrivate(this, "underlyingSource", underlyingSource);
    @putByIdDirectPrivate(this, "queue", @newQueue());
    @putByIdDirectPrivate(this, "started", false);
    @putByIdDirectPrivate(this, "closeRequested", false);
    @putByIdDirectPrivate(this, "pullAgain", false);
    @putByIdDirectPrivate(this, "pulling", false);
    @putByIdDirectPrivate(this, "strategy", @validateAndNormalizeQueuingStrategy(size, highWaterMark));

    return this;
})