Implemented ProxyObject.NoteLatest.
Implemented ProxyObject.NoteLatest.

GoogleCloudPlatform/gcsfuse,GoogleCloudPlatform/gcsfuse,jacobsa/ratelimit,BanzaiMan/gcsfuse,kahing/gcsfuse,BanzaiMan/gcsfuse,GoogleCloudPlatform/gcsfuse,mbrukman/gcsfuse,jacobsa/timeutil