Expose LogStatement properties

[epenet]

As follow-up to #787, this makes it possible to customize how we log the properties in a CustomLogger

protected override void Log(LogLevel logLevel, LogStatement logStatement)
{
  base.Log(logLevel, logStatement);
  if (LogLevel == LogLevel.LDebug)
    DebugWindow.WriteLine($"Rx: ({logStatement.Method} {logStatement.Url}) returned status code {logStatement.StatusCode}");
}