bug: panic when running with water-rs

[gaukas]

Getting panic: runtime error: nil pointer dereference when getting a connection in the Listener mode. The issue has been identified caused by the usage of the global default logger from the log package. And if we initialize a customized logger first and use that, everything worked perfectly. Investigations are underway for the issue of the default logger (since it worked with the Go runtime).

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This issue is migrated from gaukas/watm#10.

[erikziyunchi]

Solved with refraction-networking/water-rs#37