change serialize_map to serialize_struct

card_game/src/lib.rs

@@ -719,8 +719,8 @@ where
 			}
 		}
 
-		use serde::ser::SerializeMap;
-		let mut map = serializer.serialize_map(Some(2))?;
+		use serde::ser::SerializeStruct;
+		let mut map = serializer.serialize_struct("Session", 3)?;
 		// serialize the initial state of the game.
 		// if there is history, it is the first snapshot's state,
 		// otherwise it is the current game state since there are no moves.
@@ -729,9 +729,9 @@ where
 		} else {
 			&self.state.state
 		};
-		map.serialize_entry("config", &self.config)?;
-		map.serialize_entry("state", state)?;
-		map.serialize_entry("history", &History(&self.state.history))?;
+		map.serialize_field("config", &self.config)?;
+		map.serialize_field("state", state)?;
+		map.serialize_field("history", &History(&self.state.history))?;
 		map.end()
 	}
 }