func (mem *cache) RecordKnownLocation(transport types.ImageTransport, scope types.BICTransportScope, blobDigest digest.Digest, location types.BICLocationReference) {
	mem.mutex.Lock()
	defer mem.mutex.Unlock()
	key := locationKey{transport: transport.Name(), scope: scope, blobDigest: blobDigest}
	locationScope, ok := mem.knownLocations[key]
	if !ok {
		locationScope = map[types.BICLocationReference]time.Time{}
		mem.knownLocations[key] = locationScope
	}
	locationScope[location] = time.Now() // Possibly overwriting an older entry.
}
func (mem *cache) RecordKnownLocation(transport types.ImageTransport, scope types.BICTransportScope, blobDigest digest.Digest, location types.BICLocationReference) {
	mem.mutex.Lock()
	defer mem.mutex.Unlock()
	key := locationKey{transport: transport.Name(), scope: scope, blobDigest: blobDigest}
	locationScope, ok := mem.knownLocations[key]
	if !ok {
		locationScope = map[types.BICLocationReference]time.Time{}
		mem.knownLocations[key] = locationScope
	}
	locationScope[location] = time.Now() // Possibly overwriting an older entry.
}
// RecordKnownLocation records that a blob with the specified digest exists within the specified (transport, scope) scope,
// and can be reused given the opaque location data.