Protocol switch from using generators to stream-like objects. This allows the the pull side to precisely control how much data is read so that another encapsulation layer is not needed. An http client gets a response with a finite size. Because ssh clients need to keep the stream open, we must not read more data than is sent in a response. But due to the streaming nature of the changegroup scheme, only the piece that's parsing the data knows how far it's allowed to read. This means the generator scheme isn't fine-grained enough. Instead we need file-like objects with a read(x) method. This switches everything for push/pull over to using file-like objects rather than generators.

+ hg clone http://localhost:20059/ copy
requesting all changes
adding changesets
abort: error 111: Connection refused
transaction abort!
rollback completed
+ echo 255
255
+ ls copy
ls: copy: No such file or directory
+ cat
+ python dumb.py
+ sleep 2
+ hg clone http://localhost:20059/foo copy2
requesting all changes
adding changesets
abort: HTTP Error 404: File not found
transaction abort!
rollback completed
+ echo 255
255
+ set +x