submodule对gitea不管用，所以直接拉了一份拉格兰

Lagrange.Core/Lagrange.OneBot/Message/Entity/XmlSegment.cs

@@ -0,0 +1,31 @@
+using System.Text.Json.Serialization;
+using Lagrange.Core.Message;
+using Lagrange.Core.Message.Entity;
+
+namespace Lagrange.OneBot.Message.Entity;
+
+[Serializable]
+public partial class XmlSegment(string xml, int serviceid)
+{
+    public XmlSegment() : this("", 35) { }
+
+    [JsonPropertyName("data")] [CQProperty] public string Xml { get; set; } = xml;
+
+    [JsonPropertyName("service_id")] [CQProperty] public int ServiceId { get; set; } = serviceid;
+}
+
+[SegmentSubscriber(typeof(XmlEntity), "xml")]
+public partial class XmlSegment : SegmentBase
+{
+    public override void Build(MessageBuilder builder, SegmentBase segment)
+    {
+        if (segment is XmlSegment xml) builder.Xml(xml.Xml, xml.ServiceId);
+    }
+
+    public override SegmentBase FromEntity(MessageChain chain, IMessageEntity entity)
+    {
+        if (entity is not XmlEntity xmlEntity) throw new ArgumentException("Invalid entity type.");
+
+        return new XmlSegment(xmlEntity.Xml, xmlEntity.ServiceId);
+    }
+}