@throwTypeError("ReadableStreamBYOBReader needs a ReadableStream");
    if (!@isReadableByteStreamController(@getByIdDirectPrivate(stream, "readableStreamController")))
        @throwTypeError("ReadableStreamBYOBReader needs a ReadableByteStreamController");
    if (@isReadableStreamLocked(stream))
        @throwTypeError("ReadableStream is locked");

    @readableStreamReaderGenericInitialize(this, stream);
    @putByIdDirectPrivate(this, "readIntoRequests", []);

    return this;
})