List active calls, optionally filtered.
Optionalfilter: ListCallsFilterGet count of active inbound and outbound calls.
Update an active call (redirect, mute, hangup, etc).
Terminate a call.
Redirect call execution to a new webhook URL.
Inject a whisper verb (say/play) to one party on the call.
Mute or unmute a call.
Create a new outbound call.