[FEATURE] Ability to inject a callback function into an animate sequence

Is your feature request related to a problem? Please describe.
Its not straightforward to inject a trigger in the middle of an animate sequence.

Describe the solution you'd like
Ability to inject a callback function into an animate sequence to be able to trigger arbitrary code in the middle of a sequence. eg.,

animate([
  [...anim1],
  [...anim2],
  [() => {
    //do something
  }, {at: '<'}]
])

Describe alternatives you've considered
My animation is on a scroll so I use the scroll the delta to trigger, but its not a great solution.

Additional context
Tbh, maybe this is possible but im not sure from reading the docs.

Start with the animate documentation and the existing animate sequence API to determine whether callbacks are already supported. Clarify the intended callback item syntax, timing behavior, and how completion should be observed; done means the documented behavior is implemented and covered by appropriate sequence tests.