/// <inheritdoc />
public async Task JoinChatRoomAsync(string channel, string userName, Action <string> subHandler)
{
await _cacheStore.SubscribeAsync(channel, subHandler);
var history = await _cacheStore.GetAllAsync($"{PrefixKey}*");
subHandler(string.Join("\n", history));
await _cacheStore.PublishAsync(channel, $"'{userName}' joined the chat room.").ConfigureAwait(false);
}
