// Package forwarder implements a PubSub daemon for copying artifacts from one
// Google Artifact Registry instance to another.
//
// By default, it listens to the events topic for the source registry and forwards
// them to the configured destination registries. Additional subscriptions can be
// provided to forward artifacts from additional topics. Messages pushed to those
// topics may have additional fields that will direct the forwarder to route them
// to different destination registries. This functionality can be used to do things
// like re-publish messages or selectively push subsets of artifacts to specific
// projects (e.g., as part of a promotion pipeline).
//
// The functionality provided by this package is not specific to warehouse
// packages and can be used for any Google Artifact Registry instance.
package forwarder