A simple demonstration of retry logic to simulate handling an invalid token and using the refresh token

TestRefreshToken.cs

_token.AccessToken = "GARBAGE"; // simulates the same behavior as expiration
var refreshToken = false;

do
{
    if (refreshToken)
    {
        var auth = new AuthenticationClient();
        await auth.TokenRefreshAsync(ConsumerKey, _token.RefreshToken);

        _token.AccessToken = auth.AccessToken;
        refreshToken = false;
    }

    try
    {
        var client = new ForceClient(_token.InstanceUrl, _token.AccessToken, _apiVersion);
        var accounts = await client.QueryAsync<dynamic>("SELECT id, name, description FROM Account");

        // do something with accounts
    }
    catch (ForceException ex)
    {
        if (ex.Message == "Session expired or invalid")
        {
            refreshToken = true;
        }
    }

} while (refreshToken);