We switched from our custom logging to Microsoft.Extensions.Logging in #2103. Once NpgsqlDataSource is integrated, we can go further and allow setting an ILoggerFactory on it, for fully standard, DI-compatible logging.

We could (probably should?) still keep the current global/static factory injection for applications which don't want to do DbDataSource, and just fall back to it when there's no logger factory configured at the data source level. Or we could more hardline and require DbDataSource to be used if logging is desired - note that we've already broken logging anyway by switching to Microsoft.Extensions.Logging.