Consider adding a separate path for handling SNMPv3 synchronization problems

[lunkwill42]

The following part seems to ignore incoming SNMPv3 errors about synchronization issues, leaving it up to Net-SNMP to "fix" the problem when retrying:

pynetsnmp/pynetsnmp/twistedsnmp.py

Lines 239 to 244 in abf7297

	if usmStatsOidStr == ".1.3.6.1.6.3.15.1.1.2.0":
	# Some devices use usmStatsNotInTimeWindows as a normal part of the SNMPv3 handshake (JIRA-1565)
	# net-snmp automatically retries the request with the previous request_id and the values for
	# msgAuthoritativeEngineBoots and msgAuthoritativeEngineTime from this error packet
	self._log.debug("Received a usmStatsNotInTimeWindows error. Some devices use usmStatsNotInTimeWindows as a normal part of the SNMPv3 handshake.")
	return

However, if the problem persists (e.g. someone has re-used SNMP Engine IDs across multiple devices), the underlying error is actually masked by a TimeoutError being raised instead. Not very helpful when users are experiencing problems and are trying to get useful debug info.