src/vs/platform/terminal/node/ptyHostService.ts/PtyHostService/_handleHeartbeat
class PtyHostService:	private _handleHeartbeat() {
		this._clearHeartbeatTimeouts();
		this._heartbeatFirstTimeout = setTimeout(() => this._handleHeartbeatFirstTimeout(), HeartbeatConstants.BeatInterval * HeartbeatConstants.FirstWaitMultiplier);
		if (!this._isResponsive) {
			this._isResponsive = true;
			this._onPtyHostResponsive.fire();
		}
	}