dispose method

@override Future<void> dispose()

Perform cleanup

Implementation

@override
Future<void> dispose() async {
  this.manager._logger.info("Started disposing shard $id...");

  await this._receiveStream.firstWhere((element) => (element as RawApiMap)["cmd"] == "TERMINATE_OK");
  this._shardIsolate.kill(priority: Isolate.immediate);

  this.manager._logger.info("Shard $id disposed.");
}