bug: `socket.UnixConnPair()` may return error upon successfully creating pairs

[gaukas]

Cause

In e8cc8e6bdeced3115617d990f33b551714c1db66 we patched the unsafe defer as suggested by deepsource and therefore we are returning with the error returned by .Close() in a few functions.

Example

(net.Listener).Close() returns a non-crashing error without impacting the program safeness/liveness.

https://github.com/gaukas/water/actions/runs/6473922694/attempts/1

Suggested Fix

• No fix will be applied on water/socket library (otherwise it will be essentially unsafe again).
• In water when calling socket.UnixConnPair(), caller should proceed if returned error pair is not nil even when the error is non-nil.

[gaukas]

I again observed some potentially related behavior during implementing a test case. A net.Listener became closed without a party explicitly calling .Close(). Need some stable reproduce but I will just keep this for record today.

[gaukas]

Confirmed irrelevance, closing.