class_docstr: Caches URIs up to a specified total size limit.
  
  URIs are represented by strings.  Each URI has an associated size on disk.
  
  When a URI is added to the URICache, it is marked as "in use".
  When a URI is no longer in use, the user of this class should call
  `mark_unused` to signal that the URI is safe for deletion.
  
  URIs in the cache can be marked as "in use" by calling `mark_used`.
  
  Deletion of URIs on disk does not occur until the size limit is exceeded.
  When this happens, URIs that are not in use are deleted randomly until the
  size limit is satisfied, or there are no more URIs that are not in use.
  
  It is possible for the total size on disk to exceed the size limit if all
  the URIs are in use.
code: def __repr__(self):
      return str(self.__dict__)
  
file_path: ray/python/ray/_private/runtime_env/uri_cache.py
imports: import logging
  from typing import Set, Callable
label_desc: Use image node_id 9 for calling the URICache obj's underlying member method code with example usage: obj.__repr__() and returns: str