waitForAnswered
Wait for the call to reach the answered state. Returns immediately if the call
is already answered or past that state. A typed wait over waitFor().
answer() resolves when the platform accepts the command. Call
waitForAnswered() afterwards to block until the state event confirms the call
is up. A call returned by client.dial() is already answered, so this returns
at once.
Parameters
timeout
Maximum milliseconds to wait. Throws an Error if exceeded. undefined
waits indefinitely.
Returns
Promise<RelayEvent> — The state-change event.