AddKeyValue adds a (key, value) pair to the httplog associated with the request.

DefaultStacktracePred is the default implementation of StacktracePred.

LogOf returns the logger hiding in w.

StatusIsNot returns a StacktracePred which will cause stacktraces to be logged for any status *not* in the given list.

Unlogged returns the original ResponseWriter, or w if it is not our inserted logger.

WithLogging wraps the handler with logging.

ShouldLogRequestPred returns true if logging should be enabled for this request.

StacktracePred returns true if a stacktrace should be logged for this status.