trigger async mothed via another thread

[JHinW]

https://docs.microsoft.com/en-us/dotnet/standard/asynchronous-programming-patterns/calling-synchronous-methods-asynchronously

event-based async parttern:

https://docs.microsoft.com/en-us/dotnet/standard/asynchronous-programming-patterns/component-that-supports-the-event-based-asynchronous-pattern