* Add AgentWorkflowBuilder group chat
And fix a variety of issues along the way:
- Use DateTime{Offset}.UtcNow rather than Now
- AIAgentHostExecutor shouldn't be publishing empty messages
- Sequential workflows should be flowing all history and not just the output from the previous agent as the input into the next agent
- Renamed some of the new agent workflow methods... still not super happy with the shape, though
- Simplified handoffs builder, e.g. using a hashset with a custom comparer instead of a dictionary
- Improved multi-service use by trying to change assistant->user role for messages created by other agents
- Changed MessageMerger to rely on M.E.AI's coalescing more and to avoid empty contents / text
- Ensured that messages from ChatClientAgent include MessageId and CreatedAt timestamps
- Avoided including instructions for agents in a handoff workflow that don't have any handoffs
- Removed the unnecessary end function in handoffs
- Improved naming of executors to include agent name for debuggability
- Use "N" formatting with Guid.ToString everywhere, to avoid the unnecessary extra dash character which is also not valid in various places (like function tool names)
- Replace `params T[]` with `params IEnumerable<T>` to make public APIs more flexible in what they consume
* Address feedback
- Fix unintentional provider change in sample
* feat: Support Checkpoint Serialization
* Implements serialization roundtripping for checkpoints.
* Adds support for JSON serialization
* Adds FileSystem-based checkpoint persistence
* fix: Executor State does not deserialize correctly
The StateManager was not properly handling delay-deserialized values.
* Fix PortableValue handling in StateManager (this makes it delegate to PortableValue the uwnrapping)
* Fix UnitTest to actually test checkpoint serialization
* Additional review comment fixes
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Co-authored-by: Chris <66376200+crickman@users.noreply.github.com>
Stephen ToubandGitHub
