How Do I Log The Post Request for A Logout in The Default Scaffolded C# ASP.NET Core Identity Razor Pages

I need to get the exact request being sent from the browser to the server in the default dotnet C# asp.net core identity razor pages. This is the default logout function in Logout.cshtml.cs:

public async Task<IActionResult> OnPost(string returnUrl = null)
{
    await _signInManager.SignOutAsync();
    _logger.LogInformation("User logged out.");
    if (returnUrl != null)
    {
        return LocalRedirect(returnUrl);
    }
    else
    {
        return Page();
    }
}

So if I wanted to use Postman to do this function as a post request, await _signInManager.SignOutAsync();, excatly what would I put into Postman as headers and body? How do I log exactly what await _signInManager.SignOutAsync(); is sending to the server?