unpin

public final Unit unpin(OperationHandler<Boolean> handler)

This Method Not Delete channel within message. If This channel has New message, This channel Convert re- New In List display,

messageIds

Message unique ID List, at most 20

```kotlin
channel.unpin { result, error ->
    if (error == null) {
        // Deleted successfully
    }
}

pushContent = "You received a new message"