Use System.Text.Json source generation to remove some trim/AOT warnings

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientJsonSerializerContext.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.Data.SqlClient;
+
+/// <summary>
+/// Source-generated JSON metadata. Each <c>[JsonSerializable]</c> type gets a property named after its CLR type:
+/// <c>float[]</c> -> <c>SingleArray</c>, <c>ReadOnlyMemory&lt;float&gt;</c> -> <c>ReadOnlyMemorySingle</c>, <c>List&lt;byte&gt;</c> -> <c>ListByte</c>.
+/// </summary>
+[JsonSerializable(typeof(float[]))]
+[JsonSerializable(typeof(ReadOnlyMemory<float>))]
+[JsonSerializable(typeof(List<byte>))]
+internal sealed partial class SqlClientJsonSerializerContext : JsonSerializerContext
+{
+}

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlParameter.cs

@@ -2389,7 +2389,7 @@ internal static object CoerceValue(object value, MetaType destinationType, out b
                     {
                         try
                         {
-                            value = ((ISqlVector)new SqlVector<float>(JsonSerializer.Deserialize<float[]>((string)value))).VectorPayload;
+                            value = ((ISqlVector)new SqlVector<float>(JsonSerializer.Deserialize((string)value, SqlClientJsonSerializerContext.Default.SingleArray))).VectorPayload;
                         }
                         catch (Exception ex) when (ex is ArgumentNullException || ex is JsonException)
                         {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/VirtualSecureModeEnclaveProvider.cs

@@ -72,7 +72,7 @@ protected override byte[] MakeRequest(string url)
 
                     using (Stream stream = s_client.GetStreamAsync(url).ConfigureAwait(false).GetAwaiter().GetResult())
                     {
-                        return JsonSerializer.Deserialize<List<byte>>(stream)?.ToArray();
+                        return JsonSerializer.Deserialize(stream, SqlClientJsonSerializerContext.Default.ListByte)?.ToArray();
                     }
                 }
                 catch (Exception e)

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlTypes/SqlVector.cs

@@ -97,7 +97,8 @@ internal string GetString()
         {
             return SQLMessage.NullString();
         }
-        return JsonSerializer.Serialize(Memory);
+        // GetTypeFieldsOrThrow guarantees T is float.
+        return JsonSerializer.Serialize((ReadOnlyMemory<float>)(object)Memory, SqlClientJsonSerializerContext.Default.ReadOnlyMemorySingle);
     }
 
     #endregion