SideEffect concept in Temporal Ruby

In Temporal GO SDK, it is possible to add a ad-hoc activity,
sometimes it's annoying to create an activity with one single line.

I wonder if it is possible to do it in Temporal Ruby?
Something like
```ruby
ret = workflow.side_effect do |len|
SecureRandom.hex(len)
end
# or
se = workflow.build_side_effect do |len|
SecureRandom.hex(len)
end

# use it as a function
se.call(32)
```

https://docs.temporal.io/docs/java/side-effect/#:~:text=sideEffect%20is%20recorded%20into%20the,should%20only%20use%20the%20Workflow.