Code review comment for lp:~niemeyer/goamz/put-all

LGTM modulo the below.

https://codereview.appspot.com/7313081/diff/8001/s3/multi.go
File s3/multi.go (right):

https://codereview.appspot.com/7313081/diff/8001/s3/multi.go#newcode276
s3/multi.go:276: // new content.
As discussed, perhaps a comment like:
// Multipart uploads of zero length files may not work.

https://codereview.appspot.com/7313081/diff/8001/s3/multi.go#newcode284
s3/multi.go:284: current := 1 // Index of latest good part handled.
This comment is still misleading. Current isn't an index in the same way
that reuse is, and at this point we haven't any good parts, so there's
no "latest" good part - current is the part number of the next part to
handle.

https://codereview.appspot.com/7313081/