Added a property to get the KV cache size from a context

LLama.Unittest/BasicTest.cs

@@ -1,8 +1,9 @@
+using System.Text;
 using LLama.Common;
 
 namespace LLama.Unittest
 {
-    public class BasicTest
+    public sealed class BasicTest
         : IDisposable
     {
         private readonly ModelParams _params;
@@ -28,6 +29,7 @@ namespace LLama.Unittest
             Assert.Equal(32000, _model.VocabCount);
             Assert.Equal(2048, _model.ContextSize);
             Assert.Equal(4096, _model.EmbeddingSize);
+            Assert.Equal(Encoding.UTF8, _model.Encoding);
         }
 
         [Fact]

LLama.Unittest/LLamaContextTests.cs

@@ -30,6 +30,7 @@ namespace LLama.Unittest
             Assert.Equal(768, _context.ContextSize);
             Assert.Equal(4096, _context.EmbeddingSize);
             Assert.Equal(32000, _context.VocabCount);
+            Assert.Equal(0, _context.KVCacheTokenCount);
         }
     }
 }

LLama/LLamaContext.cs

@@ -41,6 +41,11 @@ namespace LLama
         /// </summary>
         public int EmbeddingSize => _ctx.EmbeddingSize;
 
+        /// <summary>
+        /// Get the number of tokens in the KV Cache for this context
+        /// </summary>
+        public int KVCacheTokenCount => _ctx.KVCacheTokenCount;
+
         /// <summary>
         /// The model params set for this model.
         /// </summary>

LLama/Native/SafeLLamaContextHandle.cs

@@ -28,6 +28,19 @@ namespace LLama.Native
         /// </summary>
         public int EmbeddingSize => ThrowIfDisposed().EmbeddingSize;
 
+        /// <summary>
+        /// Get the number of tokens in the KV Cache for this context
+        /// </summary>
+        public int KVCacheTokenCount
+        {
+            get
+            {
+                if (IsClosed)
+                    throw new ObjectDisposedException("Cannot use this `SafeLLamaContextHandle` - it has been disposed");
+                return NativeApi.llama_get_kv_cache_token_count(this);
+            }
+        }
+
         /// <summary>
         /// Get the model which this context is using
         /// </summary>