Convert buffer in range loops

fix #485

test/core/buffer_bench.cpp

@@ -66,7 +66,7 @@ public:
         std::size_t n = 0;
         using boost::asio::buffer_cast;
         using boost::asio::buffer_size;
-        for(auto const& buffer : buffers)
+        for(boost::asio::mutable_buffer buffer : buffers)
         {
             std::fill(
                 buffer_cast<char*>(buffer),

test/core/buffer_prefix.cpp

@@ -98,7 +98,7 @@ public:
         using boost::asio::buffer_size;
         std::string s;
         s.reserve(buffer_size(bs));
-        for(auto const& b : bs)
+        for(boost::asio::const_buffer b : bs)
             s.append(buffer_cast<char const*>(b),
                 buffer_size(b));
         return s;

test/core/buffer_test.hpp

@@ -30,7 +30,7 @@ to_string(ConstBufferSequence const& bs)
     using boost::asio::buffer_size;
     std::string s;
     s.reserve(buffer_size(bs));
-    for(auto const& b : bs)
+    for(boost::asio::const_buffer b : bs)
         s.append(buffer_cast<char const*>(b),
             buffer_size(b));
     return s;