1創建信號

 RACSignal *signal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
    NSLog(@"發送熱門模塊");
    [subscriber sendNext:@"熱門模塊的數據"];
    return nil;
}];

2把信號轉換成連接類

RACMulticastConnection *connection = [signal publish];

3訂閱連接類的信號

 [connection.signal subscribeNext:^(id x) {
    NSLog(@"訂閱者1%@",x);
}];

[connection.signal subscribeNext:^(id x) {
    NSLog(@"訂閱者2%@",x);
}];

[connection.signal subscribeNext:^(id x) {
    NSLog(@"訂閱者3%@",x);
}];

4連接

 [connection connect];