State persistence - session

// *** To use session, you need to configure session sevices ***
builder.Services.AddDistributedMemoryCache();
builder.Services.AddSession();

// *** Also, you need to add session middleware - right before mapping of the controllers ***
app.UseSession();

// *** Action that uses session to store some data ***
[HttpGet("[action]")]
public ActionResult<Receipt> SessionData(string? data)
{
    if (!string.IsNullOrEmpty(data))
    {
        HttpContext.Session.SetString("sessionData", data);

        return Ok($"Session data set to {data}.");
    }
    else
    {
        var storedData = HttpContext.Session.GetString("sessionData");

        return Ok($"Current session data is {storedData}.");
    }
}