The agent accepts the task at once, then works for 400 ms before finishing.

SendMessage with configuration.blocking = false: task state TASK_STATE_WORKING, returned in under 400 ms: true
SendMessage with configuration.blocking = true: task state TASK_STATE_COMPLETED, returned in at least 400 ms: true
SendMessage with no configuration at all: task state TASK_STATE_WORKING, returned in under 400 ms: true