Initial commit: Ananta CBT 4229938 private server with all fixes

Ananta.SDK/Rpc/RpcPacketWriter.cs

@@ -0,0 +1,26 @@
+using System.Buffers.Binary;
+
+namespace Ananta.SDK.Rpc;
+
+public static class RpcPacketWriter
+{
+    public static byte[] WriteNotify(uint methodId, ReadOnlySpan<byte> body)
+    {
+        var buffer = new byte[5 + body.Length];
+        buffer[0] = 0x03;
+        BinaryPrimitives.WriteUInt32LittleEndian(buffer.AsSpan(1, 4), methodId);
+        body.CopyTo(buffer.AsSpan(5));
+        return buffer;
+    }
+
+    public static byte[] WriteReturn(uint methodId, int invokeId, int err, ReadOnlySpan<byte> body)
+    {
+        var buffer = new byte[13 + body.Length];
+        buffer[0] = 0x02;
+        BinaryPrimitives.WriteUInt32LittleEndian(buffer.AsSpan(1, 4), methodId);
+        BinaryPrimitives.WriteInt32LittleEndian(buffer.AsSpan(5, 4), invokeId);
+        BinaryPrimitives.WriteInt32LittleEndian(buffer.AsSpan(9, 4), err);
+        body.CopyTo(buffer.AsSpan(13));
+        return buffer;
+    }
+}