Is your feature request related to a problem? Please describe.

The LoggingEnhancer interface enables an implementer to add extra content to a LogEntry. However, the LoggingEnhancer is not itself given any context about the underlying LogRecord, so any added content must essentially be static and unrelated to the specific log record.

Some logging systems, like flogger, subclass java.util.logging.LogRecord (e.g., flogger makes a com.google.common.flogger.backend.system.AbstractLogRecord) and add extra information (e.g., in the case of flogger, the AbstractLogRecord has getLogData().getLogSite() which offers a much more efficient and less hassle-free mechanism of retrieving log site information than com.google.cloud.logging.SourceLocation.fromCurrentContext).

Describe the solution you'd like

Can we add a LogRecord parameter to LoggingEnhancer.enhanceLogEntry? This would be a breaking change; if it's too late for such a change, maybe we need a LoggingEnhancerWithRecord or LoggingEnhancer2.

Then as a follow-on, some library can supply the glue for flogger and this library: a stock LoggingEnhancer to supply the LogSite.

Describe alternatives you've considered

We currently have a logging handler which downcasts the LogRecord, but it has its own java.util.logging.LogHandler implementation and thus doesn't use LoggingHandler or the java-logging library. I'm filing this feature request in hopes of replacing that internal implementation.

Additional context

Contact me for the internal example of downcasting LogRecord. :)