* refactor: Unify ExecutorIsh and ExecutorRegistration => ExecutorBinding
* Switch to more modern Record type-tree for Sum Types
* Unify APIs for getting ExecutorBinding
* Fix an issue where workflows consisting entirely of cross-run shareable executors which are not instance-resettable do not properly clear state when running non-concurrently.
* feat: Simplify function-to-executor pattern
* refactor: Normalize API naming
Checkpointing is used by the WorkflowHostAgent to be able to support resume from a provided thread. When a CheckpointManager is not specified, we use the InMemoryCheckpointManager and serialize its state into the thread's Serialize()ed JsonElement.
At some point InMemoryCheckpointManager became not serializable, breaking this behaviour. This change restores serializability, and adds a test.
Remove input type checking in favour of explicit `.DescribeProtocolAsync()` flow. Also removes `.AsAgentAsync()` as the validation happens at workflow run time. This makes it easier to use Workflows with DI without resorting to async-over-sync.
* feat: Add support for Workflow-as-Executor
* Fixes routing of 'object' compile-typed variables to properly take in type information
* Fixes a concurrency issue in StepTracer
* fix: Make Subworkflow ExternalRequests work properly
* fix: Threading and Concurrency fixes; prep for OffThread Mode
* refactor: Remove dead code around OffStreamRunEventStream
Currently not used, and will be replaced with a rewrite when brought back, so having it in the change is not valuable.
* ci: Work around issues with dotnet-format not properly analyzing the source
* fix: Fix the logic of AsyncCoordinator and AsyncBarrier
* Prevent individual wait cancellations from canceling the entire barrier
* Propagate information about whether the wait was completed or cancelled, and whether any waiters were present when released
* fix: Remove superfluous acces to .Keys in InProcStepTracer
* refactor: Clean up AsyncCoordinator's use of AsyncBarrier