// 如果在运行中 从worker列表中查询正在运行该job的woker，发出取消命令
// 如果在等待队列，从等待队列删除
// 如果都不在，抛出异常
CancelMessage cm=CancelMessage.newBuilder().setEk(ek).setId(id).build();
final Request req=Request.newBuilder().setRid(AtomicIncrease.getAndIncrement()).setOperate(Operate.Cancel)
.setBody(cm.toByteString()).build();
SocketMessage sm=SocketMessage.newBuilder().setKind(Kind.REQUEST).setBody(req.toByteString()).build();
Future<Response> f=context.getThreadPool().submit((new Callable<Response>() {
private Response response;
public Response call() throws Exception {
final CountDownLatch latch=new CountDownLatch(1);