fix: safety close in AsyncConnectionProvider #2935

[Roiocam]

Motivation

ConcurrentHashMap didn't guarantee the iterator consistency with entries...

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[tishun]

Hey @Roiocam

is this related to #2935?

[Roiocam]

Hey @Roiocam

is this related to #2935?

Yes, I knew it wasn't thread-safe, but my original post didn't figure out the actually reason.

I think my latest commit with a test case can strongly explain why, it also updates the solution of this issue.