diff --git a/src/Http3ResponseData.h b/src/Http3ResponseData.h
index 42047a0..6f8ad74 100644
--- a/src/Http3ResponseData.h
+++ b/src/Http3ResponseData.h
@@ -2,6 +2,7 @@
 #define UWS_H3RESPONSEDATA_H
 
 #include "MoveOnlyFunction.h"
+#include "AsyncSocketData.h"
 #include <string_view>
 
 namespace uWS {
@@ -9,12 +10,15 @@ namespace uWS {
 
         MoveOnlyFunction<void()> onAborted = nullptr;
         MoveOnlyFunction<void(std::string_view, bool)> onData = nullptr;
+        MoveOnlyFunction<bool(uintmax_t)> onWritable = nullptr;
 
-        // hasWrittenStatus
-
-        std::string buffer;
-        int bufferOffset = 0;
+        /* Status is always first header just like for h1 */
+        unsigned int headerOffset = 0;
+        
+        /* Write offset */
+        uintmax_t offset = 0;
 
+        BackPressure backpressure;
     };
 }