Number of "friends" id response is less than my following's number at the first time when I connect to "User Stream."



I’m new to use “User Stream” API. So I’d like to know about the subject.

When I connect my “User Stream” with Streaming API, Twitter system returns “friends” response.
But the number of “friends” ids, which are indicated in the first response JSON message from Twitter, is less than number of my followings that is indicated in my Twitter home.

I believe “User Stream” API give me the whole stream of my timeline, which is same as REST API’s home_timeline.
Is my understanding correct? But why are the indicated ids in “friends” so little?
Could you tell me why this happens and how I can manage to get all of “friends” list or just kindly give the URLs of explanation in similar cases.

Thanks a lot for your kind in advance.