support raw messages on apiclient->apiserver

Pilz.Net/Api/ApiRawStreamMessage.cs

@@ -3,4 +3,10 @@
 public class ApiRawStreamMessage(Stream data) : ApiRawMessage
 {
     public Stream Data { get; } = data;
+    public virtual long Length => Data.Length;
+}
+
+public class ApiRawInputStreamMessage(Stream data, long length) : ApiRawStreamMessage(data)
+{
+    public override long Length => length;
 }