Smart initial value in delay() function

[tedchwang]

Is your feature request related to a problem? Please describe.
When writing a node's formula that requires a delay function which references an influencer, it is inconvenient to specify the initial value. The initial value will also need to be changed when the influencers' history changes.

Describe the solution you'd like
Have a smart setting in the delay function that can be used to get a sensible initial value, which may be the value closest to the request time.

Describe alternatives you've considered
I have no other ideas at the moment.

Additional context
Add any other context or screenshots about the feature request here.