Added `JsonConverter` attribute, so System.Text.Json serialization is seamless

LLama.Unittest/ModelsParamsTests.cs

@@ -19,33 +19,12 @@ namespace LLama.Unittest
                 GpuLayerCount = 111
             };
 
-            var options = new System.Text.Json.JsonSerializerOptions();
-            options.Converters.Add(new SystemTextJsonEncodingConverter());
-
-            var json = System.Text.Json.JsonSerializer.Serialize(expected, options);
-            var actual = System.Text.Json.JsonSerializer.Deserialize<ModelParams>(json, options);
+            var json = System.Text.Json.JsonSerializer.Serialize(expected);
+            var actual = System.Text.Json.JsonSerializer.Deserialize<ModelParams>(json);
 
             Assert.Equal(expected, actual);
         }
 
-        private class SystemTextJsonEncodingConverter
-            : System.Text.Json.Serialization.JsonConverter<Encoding>
-
-        {
-            public override Encoding? Read(ref System.Text.Json.Utf8JsonReader reader, Type typeToConvert, System.Text.Json.JsonSerializerOptions options)
-            {
-                var name = reader.GetString();
-                if (name == null)
-                    return null;
-                return Encoding.GetEncoding(name);
-            }
-
-            public override void Write(System.Text.Json.Utf8JsonWriter writer, Encoding value, System.Text.Json.JsonSerializerOptions options)
-            {
-                writer.WriteStringValue(value.WebName);
-            }
-        }
-
         [Fact]
         public void SerializeRoundTripNewtonsoft()
         {

LLama/Common/ModelParams.cs

@@ -1,6 +1,7 @@
 using LLama.Abstractions;
 using System;
 using System.Text;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 
 namespace LLama.Common
@@ -116,6 +117,7 @@ namespace LLama.Common
         /// <summary>
         /// The encoding to use to convert text for the model
         /// </summary>
+        [JsonConverter(typeof(EncodingConverter))]
         public Encoding Encoding { get; set; } = Encoding.UTF8;
 
         /// <summary>
@@ -188,4 +190,21 @@ namespace LLama.Common
             Encoding = Encoding.GetEncoding(encoding);
         }
     }
+
+    internal class EncodingConverter
+        : JsonConverter<Encoding>
+    {
+        public override Encoding? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            var name = reader.GetString();
+            if (name == null)
+                return null;
+            return Encoding.GetEncoding(name);
+        }
+
+        public override void Write(Utf8JsonWriter writer, Encoding value, JsonSerializerOptions options)
+        {
+            writer.WriteStringValue(value.WebName);
+        }
+    }
 }