bool muted

Whether this ticker has been silenced.

While silenced, a ticker's clock can still run, but the callback will not be called.

Source 

bool get muted => _muted;
void muted=(bool value)

When set to true, silences the ticker, so that it is no longer ticking. If a tick is already scheduled, it will unschedule it. This will not unschedule the next frame, though.

When set to false, unsilences the ticker, potentially scheduling a frame to handle the next tick.

By convention, the muted property is controlled by the object that created the Ticker (typically a TickerProvider), not the object that listens to the ticker's ticks.

Source 

set muted(bool value) {
  if (value == muted)
    return;
  _muted = value;
  if (value) {
    unscheduleTick();
  } else if (shouldScheduleTick) {
    scheduleTick();
  }
}