feat: stream multipart upload

[StarAurryon]

This is the first stone to solve :
rclone/rclone#7453

What is does:

• Implements streaming with reader instead of []byte
• The rclone backend has to implement a TempBlobFactory which can be linked to the VFS or the underlying storage backend as each temp blob is created with New(bucket, object string, partNumber int, size int64)

Comments are appreciated

[ncw]

Thanks for doing this - it seems like a very good approach. I hate the naming though Factory this that and the other is giving me Java flashbacks!

How about

• Rename TempBlobFactory to: MultipartBackend
• Rename TempBlob to: UploadPart

I've given this a quick review - can you write some tests for temp.go?

I'm going to run the CI now too - the linter will complain about lots of stuff you'll need to fix. It will also complain about security problems - please ignore these - I will fix those!

[StarAurryon]

Thanks for doing this - it seems like a very good approach. I hate the naming though Factory this that and the other is giving me Java flashbacks!

How about

* Rename `TempBlobFactory` to: `MultipartBackend`

* Rename `TempBlob` to: `UploadPart`

For sure I was not sure how to name them.

I've given this a quick review - can you write some tests for temp.go?

Yes I will do it.

I'm going to run the CI now too - the linter will complain about lots of stuff you'll need to fix. It will also complain about security problems - please ignore these - I will fix those!

Ok I will try to update this end of this WE