BeginInvoke——为什么当try块中的方法抛出InvalidOperationException异常时，catc

private void f()
{
    Action<string> action = WriteLogToFile;
    AsyncCallback callBack = LogCallBack;
    action.BeginInvoke("Hello world!", callBack, action);
}
private void WriteLogToFile(string message)
{
    Monitor.Enter(locker);
    string formattedLog = Write(message);
    try
    {
        SendEmailNotifications(formattedLog);
    }
    catch (InvalidOperationException)
    {
    ...
    }
    Monitor.Exit(locker);
}
private static void LogCallBack(IAsyncResult r)
{
    if (r.IsCompleted)
    {
        ((Action<String>) r.AsyncState).EndInvoke(r);
    }
}