remove unneeded v8 cast
remove unneeded v8 cast

jut-io/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native