fix: close socket in background thread

[wind15973]

Issue #, if available:

61

Description of changes: Closing the socket in the main thread will cause UI blocking. Make sure to close the socket in the background thread.

Check points: (check or cross out if not relevant)

• [ ] ~Added new tests to cover change, if needed~
• [x] Build succeeds with all target using Swift Package Manager
• [x] All unit tests pass
• [x] Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• [ ] ~Documentation update for the change if required~
• [x] PR title conforms to conventional commit style
• [ ] ~If breaking change, documentation/changelog update with migration instructions~

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[phantumcode]

Issue #61 has been resolved/closed