An event from the TTS engine to communicate the status of an utterance.

class TtsEvent extends ChromeObject {
 TtsEvent({String type, var charIndex, String errorMessage}) {
   if (type != null) this.type = type;
   if (charIndex != null) this.charIndex = charIndex;
   if (errorMessage != null) this.errorMessage = errorMessage;
 }
 TtsEvent.fromProxy(JsObject jsProxy): super.fromProxy(jsProxy);

 /**
  * The type can be 'start' as soon as speech has started, 'word' when a word
  * boundary is reached, 'sentence' when a sentence boundary is reached,
  * 'marker' when an SSML mark element is reached, 'end' when the end of the
  * utterance is reached, 'interrupted' when the utterance is stopped or
  * interrupted before reaching the end, 'cancelled' when it's removed from the
  * queue before ever being synthesized, or 'error' when any other error
  * occurs. When pausing speech, a 'pause' event is fired if a particular
  * utterance is paused in the middle, and 'resume' if an utterance resumes
  * speech. Note that pause and resume events may not fire if speech is paused
  * in-between utterances.
  * enum of `start`, `end`, `word`, `sentence`, `marker`, `interrupted`,
  * `cancelled`, `error`, `pause`, `resume`
  */
 String get type => jsProxy['type'];
 set type(String value) => jsProxy['type'] = value;

 /**
  * The index of the current character in the utterance.
  */
 dynamic get charIndex => jsProxy['charIndex'];
 set charIndex(var value) => jsProxy['charIndex'] = jsify(value);

 /**
  * The error description, if the event type is 'error'.
  */
 String get errorMessage => jsProxy['errorMessage'];
 set errorMessage(String value) => jsProxy['errorMessage'] = value;
}