Before this change the concurrency used for an upload was rather
inconsistent.
- if size below `--backend-upload-cutoff` (default 200M) do single part upload.
- if size below `--multi-thread-cutoff` (default 256M) or using streaming
uploads (eg `rclone rcat) do multipart upload using
`--backend-upload-concurrency` to set the concurrency used by the uploader.
- otherwise do multipart upload using `--multi-thread-streams` to set the
concurrency.
This change makes the default for the concurrency used be the
`--backend-upload-concurrency`. If `--multi-thread-streams` is set and larger
than the `--backend-upload-concurrency` then that will be used instead.
This means that if the user sets `--backend-upload-concurrency` then it will be
obeyed for all multipart/multi-thread transfers and the user can override them
all with `--multi-thread-streams`.
See: #7056
This introduces a new fs.Option flag, Sensitive and uses this along
with IsPassword to redact the info in the config file for support
purposes.
It adds this flag into backends where appropriate. It was necessary to
add oauthutil.SharedOptions to some backends as they were missing
them.
Fixes#5209
Uploading 100 files of each 1 MB took 20 seconds before. With above fix it takes around 2 seconds now.
10x time improvement in line with pacer's sleep reduction from 100ms to 10ms
