Accepts the WebSocket media leg for an inbound call already delivered by the answer webhook.
Ends the call (Voice API PUT /v1/calls/:uuid → { action: 'hangup' }) and closes the media leg.
Registers the call-ended callback (event-webhook terminal status OR the WebSocket close event).
Registers the inbound DTMF callback (NCCO input/dtmf results from the event webhook).
Registers the inbound WebSocket media callback for the call (what the agent hears).
Places an outbound call via the Voice API and opens its WebSocket media leg. Returns the call UUID.
Sends DTMF digits on the call (Voice API PUT /v1/calls/:uuid/dtmf).
Transfers the live call (Voice API PUT /v1/calls/:uuid → { action: 'transfer', … }).
Writes one outbound PCM payload onto the call's WebSocket media leg (the agent's voice).
The live native call client the module hands back. The surface mirrors ITelephonyCallSdk but in the native client's own (lower-cased) vocabulary; this adapter maps between the two. VERIFY against the native Vonage Voice client.