src/java.httpclient/share/classes/java/net/http/SSLTunnelConnection.java

*** 148,157 ****
--- 148,161 ----
      protected int readImpl(ByteBuffer buf) throws IOException {
          WrapperResult r = sslDelegate.recvData(buf);
          // TODO: check for closure
          String s = "Receive) ";
          //debugPrint(s, r.buf);
+         if (r.result.bytesProduced() > 0) {
+             assert buf == r.buf;
+         }
+ 
          return r.result.bytesProduced();
      }
  
      @Override
      SocketChannel channel() {