Add back typed Part

Activout.RestClient.Test/MultipartFormDataContentTest.cs

@@ -111,6 +111,49 @@ await client.SendFormInForm(new FormModel
             Assert.Equal("bar.txt", attachment2.Headers.ContentDisposition?.FileName);
         }
 
+        [Fact]
+        public async Task TestSendFormInFormWithTypedPart()
+        {
+            // Arrange
+            var client = CreateClient();
+            var collector = new HttpRequestMessageCollector();
+
+            _mockHttp
+                .Expect(HttpMethod.Post, BaseUri + "multiparttyped")
+                .With(message =>
+                {
+                    collector.Message = message;
+                    return message.Content?.Headers.ContentType?.MediaType == "multipart/form-data";
+                })
+                .Respond(HttpStatusCode.OK);
+
+            // Act
+            await client.SendTypedParts(new[]
+            {
+                new Part<string>(Content: "foo", FileName: "foo.txt"),
+                new Part<string>(Content: "bar", FileName: "bar.txt")
+            });
+
+            // Assert
+            _mockHttp.VerifyNoOutstandingExpectation();
+
+            var multipartFormDataContent = collector.Message?.Content as MultipartFormDataContent;
+            Assert.NotNull(multipartFormDataContent);
+
+            var content = multipartFormDataContent.ToArray();
+            Assert.Equal(2, content.Length);
+
+            var attachment1 = content[0];
+            Assert.Equal("foo", await attachment1.ReadAsStringAsync());
+            Assert.Equal("attachment", attachment1.Headers.ContentDisposition?.Name);
+            Assert.Equal("foo.txt", attachment1.Headers.ContentDisposition?.FileName);
+
+            var attachment2 = content[1];
+            Assert.Equal("bar", await attachment2.ReadAsStringAsync());
+            Assert.Equal("attachment", attachment2.Headers.ContentDisposition?.Name);
+            Assert.Equal("bar.txt", attachment2.Headers.ContentDisposition?.FileName);
+        }
+
         [Fact]
         public async Task TestSendMultipartFormDataContent()
         {
@@ -186,6 +229,12 @@ Task SendFormInForm(
                 [PartParam("attachment", contentType: "application/octet-stream")]
                 Part[] parts);
 
+            [Path("typed")]
+            [Post]
+            Task SendTypedParts(
+                [PartParam("attachment", contentType: "application/octet-stream")]
+                Part<string>[] parts);
+
 
             [Post]
             Task SendParts(
@@ -214,4 +263,3 @@ private IMultipartFormDataContentClient CreateClient()
         }
     }
 }
-

Activout.RestClient/Part.cs

@@ -1,3 +1,18 @@
 namespace Activout.RestClient;
 
-public record Part(object Content, string? Name = null, string? FileName = null);
+public record Part(
+    object? Content,
+    string? Name = null,
+    string? FileName = null);
+
+public record Part<T>(
+    T Content,
+    string? Name = null,
+    string? FileName = null) : Part(Content, Name, FileName)
+{
+    public new T Content
+    {
+        get => (T)base.Content!;
+        init => base.Content = value;
+    }
+}