Add buffer_size

test/beast/http/serializer.cpp

@@ -10,6 +10,7 @@
 // Test that header file is self-contained.
 #include <boost/beast/http/serializer.hpp>
 
+#include <boost/beast/core/buffer_size.hpp>
 #include <boost/beast/http/string_body.hpp>
 #include <boost/beast/_experimental/unit_test/suite.hpp>
 
@@ -91,7 +92,6 @@ public:
         operator()(error_code&,
             ConstBufferSequence const& buffers)
         {
-            using net::buffer_size;
             size = buffer_size(buffers);
         }
     };