Update to Labs 3.5.0 (#1971)

* Merge https://github.com/Discord-Net-Labs/Discord.Net-Labs into patch/labs3.5.0

* Add missing periods

src/Discord.Net.Rest/API/Rest/UploadInteractionFileParams.cs

@@ -0,0 +1,99 @@
+using Discord.Net.Converters;
+using Discord.Net.Rest;
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord.API.Rest
+{
+    internal class UploadInteractionFileParams
+    {
+        private static JsonSerializer _serializer = new JsonSerializer { ContractResolver = new DiscordContractResolver() };
+
+        public FileAttachment[] Files { get; }
+
+        public InteractionResponseType Type { get; set; }
+        public Optional<string> Content { get; set; }
+        public Optional<bool> IsTTS { get; set; }
+        public Optional<Embed[]> Embeds { get; set; }
+        public Optional<AllowedMentions> AllowedMentions { get; set; }
+        public Optional<ActionRowComponent[]> MessageComponents { get; set; }
+        public Optional<MessageFlags> Flags { get; set; }
+
+        public bool HasData
+            => Content.IsSpecified ||
+               IsTTS.IsSpecified ||
+               Embeds.IsSpecified ||
+               AllowedMentions.IsSpecified ||
+               MessageComponents.IsSpecified ||
+               Flags.IsSpecified ||
+               Files.Any();
+
+        public UploadInteractionFileParams(params FileAttachment[] files)
+        {
+            Files = files;
+        }
+
+        public IReadOnlyDictionary<string, object> ToDictionary()
+        {
+            var d = new Dictionary<string, object>();
+           
+
+            var payload = new Dictionary<string, object>();
+            payload["type"] = Type;
+
+            var data = new Dictionary<string, object>();
+            if (Content.IsSpecified)
+                data["content"] = Content.Value;
+            if (IsTTS.IsSpecified)
+                data["tts"] = IsTTS.Value.ToString();
+            if (MessageComponents.IsSpecified)
+                data["components"] = MessageComponents.Value;
+            if (Embeds.IsSpecified)
+                data["embeds"] = Embeds.Value;
+            if (AllowedMentions.IsSpecified)
+                data["allowed_mentions"] = AllowedMentions.Value;
+            if (Flags.IsSpecified)
+                data["flags"] = Flags.Value;
+
+            List<object> attachments = new();
+
+            for (int n = 0; n != Files.Length; n++)
+            {
+                var attachment = Files[n];
+
+                var filename = attachment.FileName ?? "unknown.dat";
+                if (attachment.IsSpoiler && !filename.StartsWith(AttachmentExtensions.SpoilerPrefix))
+                    filename = filename.Insert(0, AttachmentExtensions.SpoilerPrefix);
+                d[$"files[{n}]"] = new MultipartFile(attachment.Stream, filename);
+
+                attachments.Add(new
+                {
+                    id = (ulong)n,
+                    filename = filename,
+                    description = attachment.Description ?? Optional<string>.Unspecified
+                });
+            }
+
+            data["attachments"] = attachments;
+
+            payload["data"] = data;
+
+
+            if (data.Any())
+            {
+                var json = new StringBuilder();
+                using (var text = new StringWriter(json))
+                using (var writer = new JsonTextWriter(text))
+                    _serializer.Serialize(writer, payload);
+                d["payload_json"] = json.ToString();
+            }
+
+            return d;
+        }
+    }
+}