expose underlying client instance

[BlackoutGG]

Describe the feature

There are many situations where having the client returned and painlessly accessible every where in your app is a necessity. In a scenario like redis where you need access to functionality like unlink or scanStream that aren't offered by unstorage, or other db drivers and you need more granular control.

Additional information

• Would you be willing to help implement this feature?

[Hebilicious]

Excellent idea.

[pi0]

Landed via #446