We already know!

"We shall meet where there is no darkness" (pg. 25)

So far throughout the first part of the novel, much foreshadowing has occurred. The quote given is from a dream Winston had of O'Brien and he says this. On page 179, this phrase is repeated by Winston to O'Brien because they are finally meeting like in Winston's dream. This also occurs in other parts of the story like Winston dreaming about the Golden Country and then actually seeing it with Julia. Also, the same occurs when he dreams about a naked Julia casting her clothes aside and the same thing then happens when he first makes love to her. So one thing all these foreshadows have in common is that they all take place in Winston's dreams. However, I am not exactly sure why these foreshadows exist and what function they play. One reason that I have come up with is that the author is saying that there is some type of connection between Winston's dreams and his reality. Or at the very least, the connection between the two symbolizes something. Maybe the purpose of the foreshadowing in the dreams is to say that reality barely resembles reality at all and is just a dream or an allusion. The Party has changed the past and its facts so much that what is true in the present then. Everything is about as true as a dream is true.