fix needless pass by value

Signed-off-by: Jason Volk <jason@zemos.net>

src/service/rooms/state_compressor/data.rs

@@ -60,7 +60,7 @@ impl Data {
 		})
 	}
 
-	pub(super) fn save_statediff(&self, shortstatehash: u64, diff: StateDiff) -> Result<()> {
+	pub(super) fn save_statediff(&self, shortstatehash: u64, diff: &StateDiff) -> Result<()> {
 		let mut value = diff.parent.unwrap_or(0).to_be_bytes().to_vec();
 		for new in diff.added.iter() {
 			value.extend_from_slice(&new[..]);

src/service/rooms/state_compressor/mod.rs

@@ -200,7 +200,7 @@ impl Service {
 			// There is no parent layer, create a new state
 			self.db.save_statediff(
 				shortstatehash,
-				StateDiff {
+				&StateDiff {
 					parent: None,
 					added: statediffnew,
 					removed: statediffremoved,
@@ -251,7 +251,7 @@ impl Service {
 			// Diff small enough, we add diff as layer on top of parent
 			self.db.save_statediff(
 				shortstatehash,
-				StateDiff {
+				&StateDiff {
 					parent: Some(parent.0),
 					added: statediffnew,
 					removed: statediffremoved,