difference between asyncfinished and asyncsuccess

Both properties only have meaning under certain circumstances.

AsyncFinished is meaningless unless an asynchronous operation has been started. Upon starting the asynchronous operation, AsyncFinished will be false. (Unless the asynchronous operation finishes so quickly that by the time AsyncFinished is checked it already became true.) When AsyncFinished becomes true, it is at that point that AsyncSuccess has meaning (otherwise AsyncSuccess is meaningless). In other words, once AsyncFinished becomes true, you can then check to see if the asynchronous operation was success or failure.