// Commands

    public virtual async Task <ChatMessage> Post(
        IChatService.PostCommand command, CancellationToken cancellationToken = default)
    {
        var(text, session) = command;
        var context = CommandContext.GetCurrent();

        if (Computed.IsInvalidating())
        {
            _ = PseudoGetAnyChatTail();
            return(default !);
 public Task <ChatMessage> Post([FromBody] IChatService.PostCommand command, CancellationToken cancellationToken = default)
 => _chat.Post(command.UseDefaultSession(_sessionResolver), cancellationToken);