`BroadcastChannel` drops items if there are no subscribers. Is there a way to not drop but buffer? L...

# coroutines

[Arkadii Ivanov]

BroadcastChannel drops items if there are no subscribers. Is there a way to not drop but buffer? Looking for something with UnicastSubject behaviour.

[Gabriel Feo]

I think you just need to pass a positive capacity value to the BroadcastChannel factory function
https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.channels/-broadcast-channel.html

[Arkadii Ivanov]

Nope, this is stated in docs: "Note: this channel looses all items that are send to it until the first subscriber appears;"

[Gabriel Feo]

I can’t find that, do you remember where? AFAIK, BroadcastChannel doesn’t impose that limitation

[Arkadii Ivanov]

Just open the link you provided 🙂

[Arkadii Ivanov]

message has been deleted

[Gabriel Feo]

Sounds like you need a cold stream, actually. How about a buffered Flow?

[Arkadii Ivanov]

From my point of view Flow will not buffer anything unless subscribed. Isn't it?

[Gabriel Feo]

https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/buffer.html

[Gabriel Feo]

I’m not sure

[gildor]

Yes, Flow is cold, will not buffer before start subscribing on it.
You can just open subscription on this channel and do not consume elements, so it will start buffering

[Arkadii Ivanov]

Thanks, will give it a try.