Activity type for Messages API
| Name |
|---|
| inbound |
| outbound |
| whisper |
| accept |
| forward_to_queue |
| accept_forwarding |
| intercept |
| archive |
| terminate |
| disconnect |
| start_monitoring |
| stop_monitoring |
| start_whispering |
| stop_whispering |
| start_barging_in |
| stop_barging_in |
| business_initiated_wait |
| force_close |