Edited Issue: streams - size() method returns size64_t but rest of APIs take size_t [145]

A customer discovered that our size() API on stream buffers, however the rest of the APIs for reading/writing etc... use size_t.

I'm not exactly sure how we ended up in this situation but, we should be consistent at least in the streams library. Perhaps we should make the rest of the sizes use size64_t as well. I took at look our http library uses size64_t as well when dealing with content length.