Update for Net-TS Asio (API Change):

fix #769

The following classes are removed:

* handler_type
* async_result
* async_completion
* is_dynamic_buffer
* is_const_buffer_sequence
* is_mutable_buffer_sequence
* handler_alloc

Actions Required:

* Use BOOST_ASIO_HANDLER_TYPE instead of handler_type
* Use BOOST_ASIO_INITFN_RESULT_TYPE instead of async_result
* Use boost::asio::async_completion
* Use boost::asio::is_dynamic_buffer
* Use boost::asio::is_const_buffer_sequence
* Use boost::asio::is_mutable_buffer_sequence
* boost::asio::associated_allocator_t replaces handler_alloc

test/beast/core/ostream.cpp

@@ -25,13 +25,11 @@ public:
     std::string
     to_string(ConstBufferSequence const& bs)
     {
-        using boost::asio::buffer_cast;
-        using boost::asio::buffer_size;
         std::string s;
         s.reserve(buffer_size(bs));
-        for(boost::asio::const_buffer b : bs)
-            s.append(buffer_cast<char const*>(b),
-                buffer_size(b));
+        for(auto b : beast::detail::buffers_range(bs))
+            s.append(reinterpret_cast<
+                char const*>(b.data()), b.size());
         return s;
     }