Fix D++ from stalling for a second before sending REST requests on Windows OS

[voltflake]

Quite a while ago i noticed an issue that makes windows D++ builds delay sending messages, responses, and other REST requests with 1000ms delay. This PR fixes that.

Basically i added a dummy socket into poll implementation so that when poll() is running and waiting for timeout it can be interrupted by event of that dummy socket and refresh its file descriptors on demand.

To properly test this, increase poll timeout to 5000 ms and try simple ping-pong example bot. Before this change bot would hang for 5s and only then reply. Or slightly faster if heartbeat event occurs, which triggers poll activation. Issue persisted on all platforms when using default poll socket engine, both Linux and Windows.

Feel free to pinpoint in flaws that i may missed or request changes.

• I have ensured that all methods and functions are fully documented using doxygen style comments.
  (they are as documented as they were before me)
• My code follows the coding style guide.
• I tested that my change works before raising the PR.
• I have ensured that I did not break any existing API calls.
• I have not built my pull request using AI, a static analysis tool or similar without any human oversight.

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