Fix return type issues in "SignalR API design considerations"

[JonathanBout]

Page: https://learn.microsoft.com/en-us/aspnet/core/signalr/api-design?view=aspnetcore-8.0

• A lot of functions were async and returned Task without awaiting anything which is
• Some functions had a 'void' Task as return type but actually returned a value
• Some functions returned string while that should be int

EDIT by @Rick-Anderson
Fixes #32505

[Rick-Anderson]

SignalR code is asynchronous to provide maximum scalability. I think it would be better to await.

[BrennanConroy]

There is nothing to await in the code being changed. This looks fine.

[BrennanConroy]

• Some functions had a 'void' Task as return type but actually returned a value

Where?

[Rick-Anderson]

Why not:

public async Task<string> GetTotalLengthAsync(string param1)
{
    // GetStringAsync is an async method that returns Task<string>
    string result = await GetStringAsync(param1);
    return result.Length.ToString();
}

[BrennanConroy]

Because that's just adding a new function without any reason. Returning a quick result synchronously is fine. If we are lacking docs that show results being returned asynchronously then that should be a different change.