made dispose two-phase

Author: LiamHamsters

src/Ydb.Sdk/src/Ado/Session/ImplicitSessionSource.cs

@@ -4,7 +4,8 @@ internal sealed class ImplicitSessionSource : ISessionSource
 {
     private readonly IDriver _driver;
     private readonly ManualResetEventSlim _allReleased = new(false);
-    private int _isDisposed;
+
+    private int _state;
     private int _activeLeaseCount;
 
     internal ImplicitSessionSource(IDriver driver)
@@ -24,12 +25,12 @@ public ValueTask<ISession> OpenSession(CancellationToken cancellationToken)
 
     private bool TryAcquireLease()
     {
-        if (Volatile.Read(ref _isDisposed) != 0)
+        if (Volatile.Read(ref _state) == 2)
             return false;
 
         Interlocked.Increment(ref _activeLeaseCount);
 
-        if (Volatile.Read(ref _isDisposed) != 0)
+        if (Volatile.Read(ref _state) == 2)
         {
             Interlocked.Decrement(ref _activeLeaseCount);
             return false;
@@ -40,20 +41,21 @@ private bool TryAcquireLease()
 
     internal void ReleaseLease()
     {
-        if (Interlocked.Decrement(ref _activeLeaseCount) == 0 && Volatile.Read(ref _isDisposed) != 0)
+        if (Interlocked.Decrement(ref _activeLeaseCount) == 0 && Volatile.Read(ref _state) == 1)
             _allReleased.Set();
     }
 
     public async ValueTask DisposeAsync()
     {
-        if (Interlocked.CompareExchange(ref _isDisposed, 1, 0) != 0)
+        if (Interlocked.CompareExchange(ref _state, 1, 0) != 0)
             return;
 
         if (Volatile.Read(ref _activeLeaseCount) != 0)
             _allReleased.Wait();
 
         try
         {
+            Volatile.Write(ref _state, 2);
             await _driver.DisposeAsync();
         }
         finally