RocketNet.Chat

dotnet add package RocketNet.Chat

using RocketNet.Chat;

using var httpClient = new HttpClient();

var client = new RocketChatClient(httpClient, new RocketChatClientOptions
{
    BaseAddress = new Uri("https://chat.example.com/"),
    UserId = "rbAXPnMktTFbNpwtJ",
    AuthToken = "RScctEHSmLGZ...",
});

// Look the user up, open the private chat and post into it — one call.
var posted = await client.SendDirectMessageAsync(
    RocketChatUserQuery.ByEmail("kim@example.com"),
    "Deploy finished ✅");

Console.WriteLine(posted.Message?.RoomId);