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/bench/parser/bench_parser.cpp

@@ -42,13 +42,11 @@ 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;
     }
 
@@ -172,7 +170,7 @@ public:
         isRequest, bench_parser<isRequest, Body, Fields>>
     {
         using mutable_buffers_type =
-            boost::asio::mutable_buffers_1;
+            boost::asio::mutable_buffer;
 
         void
         on_request_impl(verb, string_view,