local http_headers_proto = Proto("http_extra", "Extra analysis of the HTTP protocol");
        http_headers_proto.fields.hdr_len = ProtoField.uint32("http.hdr_len", "HTTP Header length (bytes)")
        http_headers_proto.fields.request_headers = ProtoField.string("http.request_headers", "HTTP Request Headers")
        http_headers_proto.fields.response_headers = ProtoField.string("http.response_headers", "HTTP Request Headers")

        local tcp_dissector_table = DissectorTable.get("tcp.port")
        local original_http_dissector = tcp_dissector_table:get_dissector(80)

        function http_headers_proto.dissector(tvb, pinfo, treeitem)
                original_http_dissector:call(tvb, pinfo, treeitem)
-- ...
        end

        tcp_dissector_table:add(80, http_headers_proto)

        local http_response_headers = Field.new("http.response_headers")