Upload from a stream

When I've tried to use `setUploadStream:` I got error "request body stream exhausted". After some researching I've found some topics on apple's dev forums where was said that method `-connection: needNewBodyStream:` must be implemented. 
Here are some related dissuasions with answers from apple's engineers: 
https://devforums.apple.com/message/255325#255325
https://devforums.apple.com/message/237388

Also I found that we have to set "Expect: 100-Continue" header. Here is also related answer from apple's engineer: https://devforums.apple.com/message/344093#344093

I'm not 100% sure about this code and need somebody else for comments and advices. I don't use anymore upload via stream in my project( But will be glad to help to do it possible with MKNetworkKit.

Also searching for `needNewBodyStream` during all time on apple's dev forum may give you some other interesting discussions: https://devforums.apple.com/search.jspa?q=needNewBodyStream&resultTypes=MESSAGE&peopleEnabled=true&communityID=&dateRange=all&username=