[Task]: [RRIO] [Call] Repeater invokes functional interfaces with in-between throttling

[damondouglas]

What needs to happen?

The output of this task is a Repeater that accepts functional interfaces for invoking methods and throttling inputs. While not a strict dependency, tests would be helpful to assess the Repeater as it operates in the Call PTransforms Dofn and integration tests using the mock-api.

Measures of Ready

• [Task]: [RRIO] [Call] PTransform executes user custom code without adaptive throttling #28711
• [Task]: [RRIO] [Test] Create test Caller and SetupTeardown interface implementations #28710

Measures of Done

• Tests validate that the Repeater accepts various functional interfaces that define single and no argument methods
• Tests validate that the Repeater calls the functional interfaces for the amount and order expected

Issue Priority

Priority: 2 (default / most normal work should be filed as P2)