Open decoded range options against an unknown size, producing a
negative offset for suffix ranges (eg the last N bytes) and sending
syntactically invalid Range headers which the server ignored. A
suffix range then returned the whole file instead of the requested
tail.
Decode the options against the known object size so the offset is
always absolute, only send a Range header when one was requested, and
honour the requested count when the server ignores the Range header.
The Copy method was downloading the file and uploading it again rather
than server side copying it.
It looks from the docs that the upload process can read a URL so this
might be possible, but the removed code is incorrect.
Nick Craig-Wood