Replace mock subscription with a real-life example

[chillleader]

Is your feature request related to a problem? Please describe.

Currently this repository uses a mock subscription mechanism. We received feedback that this concept is non-intuitive (not immediately clear why the inbound connector would generate events for itself).

Describe the solution you'd like

It would be nice to replace the mock subscription with something closer to the real life. For example, with a simplified version of the File Watch Connector.

Describe alternatives you've considered

Keep the current mock subscription.