Function ringingEvent

ringingEvent(hasEarlyMedia: boolean): void
Emitted when the Call has entered the ringing state. When using the Dial verb with answerOnBridge=true, the ringing state will begin when the callee has been notified of the call and will transition into open after the callee accepts the call, or closed if the call is rejected or cancelled.
Parameters
- hasEarlyMedia: boolean
  Denotes whether there is early media available from the callee. If true, the Client SDK will automatically play the early media. Sometimes this is ringing, other times it may be an important message about the call. If false, there is no remote media to play, so the application may want to play its own outgoing ringtone sound.
Returns void
Example
```
call.on('ringing', (hasEarlyMedia) => { });
```