Fix conn_test bug

[tak1827]

trafficstars

What bug?

Sometime test execution stop

The cause

Forget to runn conn.Run (The message resending process was no running)

Additional fixs

• fix fuzzing error

  • The error was program hanged (timeout 10 seconds)
  • Failing to complete sending 65536 message Within 10s in my docker -> I bought a new high performance pc

• writeAcksIfNecessary was not same as original logic so that I've adjusted.

[tak1827]

Note: fuzz error output fuzz-error.txt