- Each run's first text delta replaces the response artifact (append:false) and a resumed task
drops the previous run's response, so a failed/canceled continuation never keeps old text.
- Resumed is built from a fresh store read, history chronological (question, then answer),
timestamps on the TaskUpdater clock.
- Pool.Track refuses a second unfinished run of the same task; the pre-check rejects
continuations of a running task with UnsupportedOperation.
- Tests: continuation history, streaming continuation, response replacement, concurrent
continuation; busy test waits for the model call; TimeoutException in waits; push test
matches TASK_STATE_COMPLETED; harness cleans up on failed start.
A continued task (input-required -> new message) produced only status updates, so the SDK
answered 'Agent handler did not produce any response events'. The handler now enqueues the
resumed task (caller message and question in history, working) as the first event.
The guarded SocketsHttpHandler sets UseProxy = false: a proxy would make the connection and
skip the ConnectCallback address check.
