Lookup an item in the cache.
If the item exists, a IOStream is returned for the item. The stream may be shared by multiple callers, so ensure the stream is in a valid state through external locking.
The returned IOStream is referenced for thread-safety and must be unreferenced with unref when finished with it.
| this | |
| path |
Path to the (sub) cache the item exists in. |
| key |
Key for the cache item. |
|
a IOStream for the requested cache item, or null on error |