resolve nightly rust warnings

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/database/abstraction.rs

@@ -24,6 +24,8 @@ pub(crate) trait KeyValueDatabaseEngine: Send + Sync {
     fn memory_usage(&self) -> Result<String> {
         Ok("Current database engine does not support memory usage reporting.".to_owned())
     }
+
+    #[allow(dead_code)]
     fn clear_caches(&self) {}
 }
 

src/database/abstraction/rocksdb.rs

@@ -164,6 +164,8 @@ impl KeyValueDatabaseEngine for Arc<Engine> {
         ))
     }
 
+    // TODO: figure out if this is needed for rocksdb
+    #[allow(dead_code)]
     fn clear_caches(&self) {}
 }