[FEATURE] Async Iterator - Typed Events

[pgrayy]

Problem Statement

Currently, the events we pass to the callback handlers and also yield from are async iterator are not strongly types. This makes it challenging for users to build conditions off the events for performing actions (e.g. printing model text chunks to screen). We should formalize the structure and strongly types these event payloads.

Proposed Solution

Solution is to implement interfaces for the Agent event payloads. Could be a dataclass, TypedDict, etc.

Use Case

To configure reliable conditions on the events for performing actions real-time (e.g., printing model text to screen in a chat application of Strands).

Alternatives Solutions

No response

Additional Context

No response