AWS Step Function ECS StartedBy parameter support

Currently, the StartedBy parameter is not supported for ECS RunTask calls defined in AWS Step Function states as mentioned here: https://docs.aws.amazon.com/step-functions/latest/dg/connect-ecs.html. Just wondering if there's anything in the works for supporting this parameter. It would useful for defining a filter when collecting tasks that are started by step function executions within ECS ListTasks API calls. It would be great if it also supported passing Step Function variables and intrinsic functions (e.g. "StartedBy.$": "States.Format('{}-foo', $.some_input)".