300MB upload now takes only 20s (15MB/s)! Previously it took more than
10min, this is therefore 30x improvement.
Both tests were done on VW, locally on my machine.
This is a result of introduction of so called block streaming, that is
reading from TCP sockets in 8k blocks and writing to output (usually
file) stream as directly as possible. With as little object creation as
possible to lower garbage collection activity.