diff --git a/include/boost/asio/buffer.hpp b/include/boost/asio/buffer.hpp
index 604e70f9..ff28fa58 100644
--- a/include/boost/asio/buffer.hpp
+++ b/include/boost/asio/buffer.hpp
@@ -27,7 +27,7 @@
 #include <boost/asio/detail/pop_options.hpp>
 
 #if defined(BOOST_MSVC)
-# if defined(_HAS_ITERATOR_DEBUGGING)
+# if defined(_HAS_ITERATOR_DEBUGGING) && (_HAS_ITERATOR_DEBUGGING != 0)
 #  if !defined(BOOST_ASIO_DISABLE_BUFFER_DEBUGGING)
 #   define BOOST_ASIO_ENABLE_BUFFER_DEBUGGING
 #  endif // !defined(BOOST_ASIO_DISABLE_BUFFER_DEBUGGING)
@@ -391,6 +391,11 @@ public:
   {
   }
 
+  ~buffer_debug_check()
+  {
+    iter_ = Iterator();
+  }
+
   void operator()()
   {
     *iter_;
diff --git a/include/boost/asio/impl/read.ipp b/include/boost/asio/impl/read.ipp
index 36375911..6134b9c8 100644
--- a/include/boost/asio/impl/read.ipp
+++ b/include/boost/asio/impl/read.ipp
@@ -19,7 +19,6 @@
 
 #include <boost/asio/detail/push_options.hpp>
 #include <algorithm>
-#include <boost/optional.hpp>
 #include <boost/asio/detail/pop_options.hpp>
 
 #include <boost/asio/buffer.hpp>
@@ -140,25 +139,23 @@ namespace detail
         std::size_t bytes_transferred)
     {
       total_transferred_ += bytes_transferred;
-      buffers_->consume(bytes_transferred);
-      if ((*completion_condition_)(ec, total_transferred_)
-          || buffers_->begin() == buffers_->end())
+      buffers_.consume(bytes_transferred);
+      if (completion_condition_(ec, total_transferred_)
+          || buffers_.begin() == buffers_.end())
       {
-        buffers_.reset();
-        completion_condition_.reset();
         handler_(ec, total_transferred_);
       }
       else
       {
-        stream_.async_read_some(*buffers_, *this);
+        stream_.async_read_some(buffers_, *this);
       }
     }
 
   //private:
     AsyncReadStream& stream_;
-    boost::optional<buffers_type> buffers_;
+    buffers_type buffers_;
     std::size_t total_transferred_;
-    boost::optional<CompletionCondition> completion_condition_;
+    CompletionCondition completion_condition_;
     ReadHandler handler_;
   };
 
@@ -239,9 +236,8 @@ namespace detail
       total_transferred_ += bytes_transferred;
       streambuf_.commit(bytes_transferred);
       if (streambuf_.size() == streambuf_.max_size()
-          || (*completion_condition_)(ec, total_transferred_))
+          || completion_condition_(ec, total_transferred_))
       {
-        completion_condition_.reset();
         handler_(ec, total_transferred_);
       }
       else
@@ -256,7 +252,7 @@ namespace detail
     AsyncReadStream& stream_;
     boost::asio::basic_streambuf<Allocator>& streambuf_;
     std::size_t total_transferred_;
-    boost::optional<CompletionCondition> completion_condition_;
+    CompletionCondition completion_condition_;
     ReadHandler handler_;
   };
 
diff --git a/include/boost/asio/impl/write.ipp b/include/boost/asio/impl/write.ipp
index c35ea4aa..8073bfdd 100644
--- a/include/boost/asio/impl/write.ipp
+++ b/include/boost/asio/impl/write.ipp
@@ -17,10 +17,6 @@
 
 #include <boost/asio/detail/push_options.hpp>
 
-#include <boost/asio/detail/push_options.hpp>
-#include <boost/optional.hpp>
-#include <boost/asio/detail/pop_options.hpp>
-
 #include <boost/asio/buffer.hpp>
 #include <boost/asio/completion_condition.hpp>
 #include <boost/asio/detail/bind_handler.hpp>
@@ -129,25 +125,23 @@ namespace detail
         std::size_t bytes_transferred)
     {
       total_transferred_ += bytes_transferred;
-      buffers_->consume(bytes_transferred);
-      if ((*completion_condition_)(ec, total_transferred_)
-          || buffers_->begin() == buffers_->end())
+      buffers_.consume(bytes_transferred);
+      if (completion_condition_(ec, total_transferred_)
+          || buffers_.begin() == buffers_.end())
       {
-        buffers_.reset();
-        completion_condition_.reset();
         handler_(ec, total_transferred_);
       }
       else
       {
-        stream_.async_write_some(*buffers_, *this);
+        stream_.async_write_some(buffers_, *this);
       }
     }
 
   //private:
     AsyncWriteStream& stream_;
-    boost::optional<buffers_type> buffers_;
+    buffers_type buffers_;
     std::size_t total_transferred_;
-    boost::optional<CompletionCondition> completion_condition_;
+    CompletionCondition completion_condition_;
     WriteHandler handler_;
   };