fix load null frame for reset local session

Author: lucasteles

src/Backdash/Session/Backends/LocalSession.cs

@@ -310,6 +310,7 @@ void DiscardInputsAfter(Frame frame)
     void ResetInputQueues()
     {
         CurrentFrame = Frame.Zero;
+        stateStore.Clear();
         ref var current = ref MemoryMarshal.GetReference(inputQueues.AsSpan());
         ref var limit = ref Unsafe.Add(ref current, inputQueues.Length);
         while (Unsafe.IsAddressLessThan(ref current, ref limit))

src/Backdash/Synchronizing/State/DefaultStateStore.cs

@@ -18,13 +18,21 @@ public sealed class DefaultStateStore(int hintSize) : IStateStore
     public void Initialize(int saveCount)
     {
         savedStates = new SavedState[saveCount];
-        for (var i = 0; i < saveCount; i++)
-            savedStates[i] = new(Frame.Null, new(hintSize), Checksum.Empty);
+        for (var i = 0; i < savedStates.Length; i++)
+            savedStates[i] = new(hintSize);
     }
 
     /// <inheritdoc />
     public void Advance() => head = (head + 1) % savedStates.Length;
 
+    /// <inheritdoc />
+    public void Clear()
+    {
+        head = 0;
+        foreach (var state in savedStates)
+            state.Clear();
+    }
+
     /// <inheritdoc />
     public ref SavedState Next()
     {

src/Backdash/Synchronizing/State/IStateStore.cs

@@ -45,6 +45,11 @@ public interface IStateStore
     /// </summary>
     void Advance();
 
+    /// <summary>
+    ///     Clear all saved states
+    /// </summary>
+    void Clear();
+
     /// <summary>
     ///     Return a <see cref="SavedState" /> for <paramref name="frame" /> if exists, <see langword="null" /> otherwise.
     /// </summary>

src/Backdash/Synchronizing/State/SavedState.cs

@@ -11,6 +11,9 @@ namespace Backdash.Synchronizing.State;
 /// <param name="Checksum">Checksum of state</param>
 public sealed record SavedState(Frame Frame, ArrayBufferWriter<byte> GameState, Checksum Checksum)
 {
+    /// <inheritdoc />
+    public SavedState(int hintSize) : this(Frame.Null, new(hintSize), Checksum.Empty) { }
+
     /// <summary>Saved frame number</summary>
     public Frame Frame = Frame;
 
@@ -25,4 +28,12 @@ public sealed record SavedState(Frame Frame, ArrayBufferWriter<byte> GameState,
 
     /// <summary>Returns a snapshot of the current saved state</summary>
     public StateSnapshot ToSnapshot() => new(Frame, Checksum, GameState.WrittenSpan.ToArray());
+
+    /// <summary>Clear current saved state</summary>
+    public void Clear()
+    {
+        Frame = Frame.Null;
+        Checksum = Checksum.Empty;
+        GameState.Clear();
+    }
 }