+ """Base class for maintaining object lifecycle.
+
+ Functions include:
+
+ * Indicate if an object is up to date (stale() == false) or needs to be
+ updated sets stale() == True). Use invalidate() to mark the object as
+ stale. An object is also automatically stale if it has not been updated
+ in `_poll_time` seconds.
+
+ * Record access time (atime) timestamp
+
+ * Manage internal use count used by the inode cache ("inc_use" and
+ "dec_use"). An object which is in use cannot be cleared by the inode
+ cache.
+
+ * Manage the kernel reference count ("inc_ref" and "dec_ref"). An object
+ which is referenced by the kernel cannot have its inode entry deleted.
+
+ * Record cache footprint, cache priority
+
+ * Record Arvados uuid at the time the object is placed in the cache
+
+ * Clear the object contents (invalidates the object)
+
+ """