feat: add unwrap method

Author: achingbrain

packages/interface-blockstore/src/adapter.js

@@ -240,6 +240,10 @@ class BlockstoreAdapter {
 
     return it
   }
+
+  unwrap () {
+    return this
+  }
 }
 
 module.exports = BlockstoreAdapter

packages/interface-datastore/src/adapter.js

@@ -225,6 +225,10 @@ class Adapter {
 
     return it
   }
+
+  unwrap () {
+    return this
+  }
 }
 
 module.exports = Adapter

packages/interface-store/src/index.d.ts

@@ -172,6 +172,11 @@ export interface Store<Key, Value> {
    * ```
    */
    queryKeys: (query: KeyQuery<Key>, options?: Options) => AsyncIterable<Key>
+
+   /**
+    * Where a store wraps another store, return the wrapped store
+    */
+   unwrap: () => Store<Key, Value>
 }
 
 export type QueryFilter<Key, Value> = (item: Pair<Key, Value>) => boolean