fix: Cache JsonSerializerOptions for NordigenHttpClient

This reduces execution time and memory allocation for GetRequiredService<INordigenClient>() by an order of magnitude

source/VMelnalksnis.NordigenDotNet.DependencyInjection/ServiceCollectionExtensions.cs

@@ -73,6 +73,7 @@ public static class ServiceCollectionExtensions
 
 		return serviceCollection
 			.AddSingleton<NordigenTokenCache>()
+			.AddSingleton<NordigenJsonSerializerOptions>()
 			.AddTransient<INordigenClient, NordigenClient>()
 			.AddTransient<IAccountClient, AccountClient>()
 			.AddTransient<IAgreementClient, AgreementClient>()

source/VMelnalksnis.NordigenDotNet/NordigenHttpClient.cs

@@ -7,13 +7,9 @@ using System.Net.Http;
 using System.Net.Http.Json;
 using System.Runtime.CompilerServices;
 using System.Text.Json;
-using System.Text.Json.Serialization;
 using System.Threading;
 using System.Threading.Tasks;
 
-using NodaTime;
-using NodaTime.Serialization.SystemTextJson;
-
 namespace VMelnalksnis.NordigenDotNet;
 
 /// <summary><see cref="HttpClient"/> wrapper that uses the correct serialization settings for all requests.</summary>
@@ -24,15 +20,11 @@ public sealed class NordigenHttpClient
 
 	/// <summary>Initializes a new instance of the <see cref="NordigenHttpClient"/> class.</summary>
 	/// <param name="httpClient">Http client configured for making requests to the Nordigen API.</param>
-	/// <param name="dateTimeZoneProvider">Time zone provider for date and time serialization.</param>
-	public NordigenHttpClient(HttpClient httpClient, IDateTimeZoneProvider dateTimeZoneProvider)
+	/// <param name="nordigenJsonSerializerOptions">Nordigen specific instance of <see cref="JsonSerializerOptions"/>.</param>
+	public NordigenHttpClient(HttpClient httpClient, NordigenJsonSerializerOptions nordigenJsonSerializerOptions)
 	{
 		_httpClient = httpClient;
-
-		_serializerOptions = new JsonSerializerOptions(JsonSerializerDefaults.Web)
-		{
-			Converters = { new JsonStringEnumConverter() },
-		}.ConfigureForNodaTime(dateTimeZoneProvider);
+		_serializerOptions = nordigenJsonSerializerOptions.Options;
 	}
 
 	internal async Task<TResult?> Get<TResult>(string requestUri, CancellationToken cancellationToken)

source/VMelnalksnis.NordigenDotNet/NordigenJsonSerializerOptions.cs

@@ -0,0 +1,27 @@
+// Copyright 2022 Valters Melnalksnis
+// Licensed under the Apache License 2.0.
+// See LICENSE file in the project root for full license information.
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+using NodaTime;
+using NodaTime.Serialization.SystemTextJson;
+
+namespace VMelnalksnis.NordigenDotNet;
+
+/// <summary><see cref="JsonSerializerOptions"/> for <see cref="NordigenHttpClient"/>.</summary>
+public sealed class NordigenJsonSerializerOptions
+{
+	/// <summary>Initializes a new instance of the <see cref="NordigenJsonSerializerOptions"/> class.</summary>
+	/// <param name="dateTimeZoneProvider">Time zone provider for date and time serialization.</param>
+	public NordigenJsonSerializerOptions(IDateTimeZoneProvider dateTimeZoneProvider)
+	{
+		Options = new JsonSerializerOptions(JsonSerializerDefaults.Web)
+		{
+			Converters = { new JsonStringEnumConverter() },
+		}.ConfigureForNodaTime(dateTimeZoneProvider);
+	}
+
+	internal JsonSerializerOptions Options { get; }
+}