Use new .NET APIs

- Use `Convert.ToHexStringLower()`.
- Use `CryptographicOperations.HashData()`.

samples/MinimalApi/Program.cs

@@ -55,23 +55,25 @@
     }
 
     byte[] buffer = Encoding.UTF8.GetBytes(request.Plaintext ?? string.Empty);
-    byte[] hash = request.Algorithm.ToUpperInvariant() switch
+    HashAlgorithmName? hashAlgorithm = request.Algorithm.ToUpperInvariant() switch
     {
-        "MD5" => MD5.HashData(buffer),
-        "SHA1" => SHA1.HashData(buffer),
-        "SHA256" => SHA256.HashData(buffer),
-        "SHA384" => SHA384.HashData(buffer),
-        "SHA512" => SHA512.HashData(buffer),
-        _ => [],
+        "MD5" => HashAlgorithmName.MD5,
+        "SHA1" => HashAlgorithmName.SHA1,
+        "SHA256" => HashAlgorithmName.SHA256,
+        "SHA384" => HashAlgorithmName.SHA384,
+        "SHA512" => HashAlgorithmName.SHA512,
+        _ => null,
     };
 
-    if (hash.Length == 0)
+    if (hashAlgorithm is not { } algorithm)
     {
         return Results.Problem(
             $"The specified hash algorithm '{request.Algorithm}' is not supported.",
             statusCode: StatusCodes.Status400BadRequest);
     }
 
+    byte[] hash = CryptographicOperations.HashData(algorithm, buffer);
+
     var result = new HashResponse()
     {
         Hash = formatAsBase64 == true ? Convert.ToBase64String(hash) : Convert.ToHexString(hash),

src/AwsLambdaTestServer/RuntimeHandler.cs

@@ -274,11 +274,15 @@ internal async Task HandleInitializationErrorAsync(HttpContext httpContext)
     /// </remarks>
     private static string GenerateTraceId()
     {
-#pragma warning disable CA1308
         var epoch = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
         var buffer = RandomNumberGenerator.GetBytes(96 / 8);
+#if NET9_0_OR_GREATER
+        var identifier = Convert.ToHexStringLower(buffer);
+#else
+#pragma warning disable CA1308
         var identifier = Convert.ToHexString(buffer).ToLowerInvariant();
 #pragma warning restore CA1308
+#endif
 
         return FormattableString.Invariant($"Root=1-{epoch:x8}-{identifier}");
     }