Logger implements a shared logging infrastructure. It add several features on top of the standard logging package:

• The usual log levels, from trace up to panic.
• Logs are created for named services, each of which can log at its own log level.
• Eacch log has a group number that can be used to group related log entries.
• Each log entry has a globally unique sequence number that can be used to reconstruct the order in which log entries were generated even in the face of out-of-order log recording.
• Logs can have callback functions registered for them to facilitate sending log entries as events.