diff --git a/CHANGELOG.md b/CHANGELOG.md
index df471fc2..6e8c760f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ Version 149:
 * Fix CMakeLists.txt variable
 * Protect calls from macros
 * pausation always allocates
+* Don't copy completion handlers
 
 --------------------------------------------------------------------------------
 
diff --git a/include/boost/beast/core/detail/bind_handler.hpp b/include/boost/beast/core/detail/bind_handler.hpp
index 50b0ce7c..5f5c612b 100644
--- a/include/boost/beast/core/detail/bind_handler.hpp
+++ b/include/boost/beast/core/detail/bind_handler.hpp
@@ -109,7 +109,7 @@ public:
         boost::asio::associated_allocator_t<Handler>;
 
     bound_handler(bound_handler&&) = default;
-    bound_handler(bound_handler const&) = default;
+    bound_handler(bound_handler const&) = delete;
 
     template<class DeducedHandler>
     explicit
diff --git a/include/boost/beast/core/impl/buffered_read_stream.ipp b/include/boost/beast/core/impl/buffered_read_stream.ipp
index bf92990f..3e6b935f 100644
--- a/include/boost/beast/core/impl/buffered_read_stream.ipp
+++ b/include/boost/beast/core/impl/buffered_read_stream.ipp
@@ -37,7 +37,7 @@ class buffered_read_stream<
 
 public:
     read_some_op(read_some_op&&) = default;
-    read_some_op(read_some_op const&) = default;
+    read_some_op(read_some_op const&) = delete;
 
     template<class DeducedHandler, class... Args>
     read_some_op(DeducedHandler&& h,
@@ -237,7 +237,7 @@ async_read_some(
         void(error_code, std::size_t)> init{handler};
     read_some_op<MutableBufferSequence, BOOST_ASIO_HANDLER_TYPE(
         ReadHandler, void(error_code, std::size_t))>{
-            init.completion_handler, *this, buffers}(
+            std::move(init.completion_handler), *this, buffers}(
                 error_code{}, 0);
     return init.result.get();
 }
diff --git a/include/boost/beast/core/type_traits.hpp b/include/boost/beast/core/type_traits.hpp
index d622e0e8..3c52d60f 100644
--- a/include/boost/beast/core/type_traits.hpp
+++ b/include/boost/beast/core/type_traits.hpp
@@ -52,7 +52,7 @@ template<class T, class Signature>
 using is_completion_handler = std::integral_constant<bool, ...>;
 #else
 using is_completion_handler = std::integral_constant<bool,
-    std::is_copy_constructible<typename std::decay<T>::type>::value &&
+    std::is_move_constructible<typename std::decay<T>::type>::value &&
     detail::is_invocable<T, Signature>::value>;
 #endif
 
diff --git a/include/boost/beast/http/impl/file_body_win32.ipp b/include/boost/beast/http/impl/file_body_win32.ipp
index 6d302c96..2ed08da5 100644
--- a/include/boost/beast/http/impl/file_body_win32.ipp
+++ b/include/boost/beast/http/impl/file_body_win32.ipp
@@ -344,7 +344,7 @@ class write_some_win32_op
 
 public:
     write_some_win32_op(write_some_win32_op&&) = default;
-    write_some_win32_op(write_some_win32_op const&) = default;
+    write_some_win32_op(write_some_win32_op const&) = delete;
 
     template<class DeducedHandler>
     write_some_win32_op(
@@ -422,7 +422,10 @@ operator()()
             (std::min<std::uint64_t>)(r.body_.last_ - r.pos_, sr_.limit()),
             (std::numeric_limits<boost::winapi::DWORD_>::max)()));
     boost::asio::windows::overlapped_ptr overlapped{
-        sock_.get_executor().context(), *this};
+        sock_.get_executor().context(), std::move(*this)};
+    // Note that we have moved *this, so we cannot access
+    // the handler since it is now moved-from. We can still
+    // access simple things like references and built-in types.
     auto& ov = *overlapped.get();
     ov.Offset = lowPart(r.pos_);
     ov.OffsetHigh = highPart(r.pos_);
@@ -569,7 +572,7 @@ async_write_some(
         BOOST_ASIO_HANDLER_TYPE(WriteHandler,
             void(error_code, std::size_t)),
         isRequest, Fields>{
-            init.completion_handler, sock, sr}();
+            std::move(init.completion_handler), sock, sr}();
     return init.result.get();
 }
 
diff --git a/include/boost/beast/http/impl/read.ipp b/include/boost/beast/http/impl/read.ipp
index ee55131d..cbabff0f 100644
--- a/include/boost/beast/http/impl/read.ipp
+++ b/include/boost/beast/http/impl/read.ipp
@@ -50,7 +50,7 @@ class read_some_op
 
 public:
     read_some_op(read_some_op&&) = default;
-    read_some_op(read_some_op const&) = default;
+    read_some_op(read_some_op const&) = delete;
 
     template<class DeducedHandler>
     read_some_op(DeducedHandler&& h, Stream& s,
@@ -208,7 +208,7 @@ class read_op
 
 public:
     read_op(read_op&&) = default;
-    read_op(read_op const&) = default;
+    read_op(read_op const&) = delete;
 
     template<class DeducedHandler>
     read_op(DeducedHandler&& h, Stream& s,
@@ -331,7 +331,7 @@ class read_msg_op
 
 public:
     read_msg_op(read_msg_op&&) = default;
-    read_msg_op(read_msg_op const&) = default;
+    read_msg_op(read_msg_op const&) = delete;
 
     template<class DeducedHandler, class... Args>
     read_msg_op(DeducedHandler&& h, Stream& s, Args&&... args)
@@ -531,7 +531,7 @@ async_read_some(
     detail::read_some_op<AsyncReadStream,
         DynamicBuffer, isRequest, Derived, BOOST_ASIO_HANDLER_TYPE(
             ReadHandler, void(error_code, std::size_t))>{
-                init.completion_handler, stream, buffer, parser}(
+                std::move(init.completion_handler), stream, buffer, parser}(
                     {}, 0, false);
     return init.result.get();
 }
@@ -619,8 +619,8 @@ async_read_header(
     detail::read_op<AsyncReadStream, DynamicBuffer,
         isRequest, Derived, detail::parser_is_header_done,
             BOOST_ASIO_HANDLER_TYPE(ReadHandler, void(error_code, std::size_t))>{
-                init.completion_handler, stream, buffer, parser}(
-                    {}, 0, false);
+                std::move(init.completion_handler), stream,
+                buffer, parser}({}, 0, false);
     return init.result.get();
 }
 
@@ -708,7 +708,7 @@ async_read(
     detail::read_op<AsyncReadStream, DynamicBuffer,
         isRequest, Derived, detail::parser_is_done,
             BOOST_ASIO_HANDLER_TYPE(ReadHandler, void(error_code, std::size_t))>{
-                init.completion_handler, stream, buffer, parser}(
+                std::move(init.completion_handler), stream, buffer, parser}(
                     {}, 0, false);
     return init.result.get();
 }
@@ -803,7 +803,7 @@ async_read(
         isRequest, Body, Allocator,
         BOOST_ASIO_HANDLER_TYPE(
             ReadHandler, void(error_code, std::size_t))>{
-                init.completion_handler, stream, buffer, msg}(
+                std::move(init.completion_handler), stream, buffer, msg}(
                     {}, 0, false);
     return init.result.get();
 }
diff --git a/include/boost/beast/http/impl/write.ipp b/include/boost/beast/http/impl/write.ipp
index 87434297..c07fe540 100644
--- a/include/boost/beast/http/impl/write.ipp
+++ b/include/boost/beast/http/impl/write.ipp
@@ -67,7 +67,7 @@ class write_some_op
 
 public:
     write_some_op(write_some_op&&) = default;
-    write_some_op(write_some_op const&) = default;
+    write_some_op(write_some_op const&) = delete;
 
     template<class DeducedHandler>
     write_some_op(DeducedHandler&& h, Stream& s,
@@ -203,7 +203,7 @@ class write_op
 
 public:
     write_op(write_op&&) = default;
-    write_op(write_op const&) = default;
+    write_op(write_op const&) = delete;
 
     template<class DeducedHandler>
     write_op(DeducedHandler&& h, Stream& s,
@@ -318,7 +318,7 @@ class write_msg_op
 
 public:
     write_msg_op(write_msg_op&&) = default;
-    write_msg_op(write_msg_op const&) = default;
+    write_msg_op(write_msg_op const&) = delete;
 
     template<class DeducedHandler, class... Args>
     write_msg_op(DeducedHandler&& h, Stream& s, Args&&... args)
@@ -479,7 +479,7 @@ async_write_some_impl(
         BOOST_ASIO_HANDLER_TYPE(WriteHandler,
             void(error_code, std::size_t)),
         isRequest, Body, Fields>{
-            init.completion_handler, stream, sr}();
+            std::move(init.completion_handler), stream, sr}();
     return init.result.get();
 }
 
@@ -638,7 +638,7 @@ async_write_header(
             void(error_code, std::size_t)),
         detail::serializer_is_header_done,
         isRequest, Body, Fields>{
-        init.completion_handler, stream, sr}();
+        std::move(init.completion_handler), stream, sr}();
     return init.result.get();
 }
 
@@ -715,7 +715,7 @@ async_write(
             void(error_code, std::size_t)),
         detail::serializer_is_done,
         isRequest, Body, Fields>{
-            init.completion_handler, stream, sr}();
+            std::move(init.completion_handler), stream, sr}();
     return init.result.get();
 }
 
@@ -788,7 +788,7 @@ async_write(
         BOOST_ASIO_HANDLER_TYPE(WriteHandler,
             void(error_code, std::size_t)),
         isRequest, Body, Fields>{
-            init.completion_handler, stream, msg}();
+            std::move(init.completion_handler), stream, msg}();
     return init.result.get();
 }
 
diff --git a/include/boost/beast/websocket/impl/accept.ipp b/include/boost/beast/websocket/impl/accept.ipp
index dd74dad3..8b29de46 100644
--- a/include/boost/beast/websocket/impl/accept.ipp
+++ b/include/boost/beast/websocket/impl/accept.ipp
@@ -58,7 +58,7 @@ class stream<NextLayer>::response_op
 
 public:
     response_op(response_op&&) = default;
-    response_op(response_op const&) = default;
+    response_op(response_op const&) = delete;
 
     template<class DeducedHandler, class... Args>
     response_op(DeducedHandler&& h,
@@ -154,7 +154,7 @@ class stream<NextLayer>::accept_op
 
 public:
     accept_op(accept_op&&) = default;
-    accept_op(accept_op const&) = default;
+    accept_op(accept_op const&) = delete;
 
     template<class DeducedHandler, class... Args>
     accept_op(DeducedHandler&& h,
@@ -545,7 +545,7 @@ async_accept(
         decltype(&default_decorate_res),
         BOOST_ASIO_HANDLER_TYPE(
             AcceptHandler, void(error_code))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 &default_decorate_res}({});
     return init.result.get();
@@ -574,7 +574,7 @@ async_accept_ex(
         ResponseDecorator,
         BOOST_ASIO_HANDLER_TYPE(
             AcceptHandler, void(error_code))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 decorator}({});
     return init.result.get();
@@ -605,7 +605,7 @@ async_accept(
         decltype(&default_decorate_res),
         BOOST_ASIO_HANDLER_TYPE(
             AcceptHandler, void(error_code))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 &default_decorate_res}.run(buffers);
     return init.result.get();
@@ -641,7 +641,7 @@ async_accept_ex(
         ResponseDecorator,
         BOOST_ASIO_HANDLER_TYPE(
             AcceptHandler, void(error_code))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 decorator}.run(buffers);
     return init.result.get();
@@ -667,7 +667,7 @@ async_accept(
     response_op<
         BOOST_ASIO_HANDLER_TYPE(
             AcceptHandler, void(error_code))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 req,
                 &default_decorate_res}();
@@ -699,7 +699,7 @@ async_accept_ex(
     response_op<
         BOOST_ASIO_HANDLER_TYPE(
             AcceptHandler, void(error_code))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 req,
                 decorator}();
diff --git a/include/boost/beast/websocket/impl/close.ipp b/include/boost/beast/websocket/impl/close.ipp
index bf1b043e..e2b61318 100644
--- a/include/boost/beast/websocket/impl/close.ipp
+++ b/include/boost/beast/websocket/impl/close.ipp
@@ -64,7 +64,7 @@ class stream<NextLayer>::close_op
 
 public:
     close_op(close_op&&) = default;
-    close_op(close_op const&) = default;
+    close_op(close_op const&) = delete;
 
     template<class DeducedHandler>
     close_op(
@@ -447,7 +447,7 @@ async_close(close_reason const& cr, CloseHandler&& handler)
         void(error_code)> init{handler};
     close_op<BOOST_ASIO_HANDLER_TYPE(
         CloseHandler, void(error_code))>{
-            init.completion_handler, *this, cr}(
+            std::move(init.completion_handler), *this, cr}(
                 {}, 0, false);
     return init.result.get();
 }
diff --git a/include/boost/beast/websocket/impl/handshake.ipp b/include/boost/beast/websocket/impl/handshake.ipp
index 911265f3..18fd1e06 100644
--- a/include/boost/beast/websocket/impl/handshake.ipp
+++ b/include/boost/beast/websocket/impl/handshake.ipp
@@ -65,7 +65,7 @@ class stream<NextLayer>::handshake_op
 
 public:
     handshake_op(handshake_op&&) = default;
-    handshake_op(handshake_op const&) = default;
+    handshake_op(handshake_op const&) = delete;
 
     template<class DeducedHandler, class... Args>
     handshake_op(DeducedHandler&& h,
@@ -161,7 +161,7 @@ async_handshake(string_view host,
         void(error_code)> init{handler};
     handshake_op<BOOST_ASIO_HANDLER_TYPE(
         HandshakeHandler, void(error_code))>{
-            init.completion_handler, *this, nullptr, host,
+            std::move(init.completion_handler), *this, nullptr, host,
                 target, &default_decorate_req}();
     return init.result.get();
 }
@@ -182,7 +182,7 @@ async_handshake(response_type& res,
         void(error_code)> init{handler};
     handshake_op<BOOST_ASIO_HANDLER_TYPE(
         HandshakeHandler, void(error_code))>{
-            init.completion_handler, *this, &res, host,
+            std::move(init.completion_handler), *this, &res, host,
                 target, &default_decorate_req}();
     return init.result.get();
 }
@@ -206,7 +206,7 @@ async_handshake_ex(string_view host,
         void(error_code)> init{handler};
     handshake_op<BOOST_ASIO_HANDLER_TYPE(
         HandshakeHandler, void(error_code))>{
-            init.completion_handler, *this, nullptr, host,
+            std::move(init.completion_handler), *this, nullptr, host,
                 target, decorator}();
     return init.result.get();
 }
@@ -231,7 +231,7 @@ async_handshake_ex(response_type& res,
         void(error_code)> init{handler};
     handshake_op<BOOST_ASIO_HANDLER_TYPE(
         HandshakeHandler, void(error_code))>{
-            init.completion_handler, *this, &res, host,
+            std::move(init.completion_handler), *this, &res, host,
                 target, decorator}();
     return init.result.get();
 }
diff --git a/include/boost/beast/websocket/impl/ping.ipp b/include/boost/beast/websocket/impl/ping.ipp
index 0ce869d1..223d06a7 100644
--- a/include/boost/beast/websocket/impl/ping.ipp
+++ b/include/boost/beast/websocket/impl/ping.ipp
@@ -62,7 +62,7 @@ class stream<NextLayer>::ping_op
 
 public:
     ping_op(ping_op&&) = default;
-    ping_op(ping_op const&) = default;
+    ping_op(ping_op const&) = delete;
 
     template<class DeducedHandler>
     ping_op(
@@ -241,7 +241,7 @@ async_ping(ping_data const& payload, WriteHandler&& handler)
         void(error_code)> init{handler};
     ping_op<BOOST_ASIO_HANDLER_TYPE(
         WriteHandler, void(error_code))>{
-            init.completion_handler, *this,
+            std::move(init.completion_handler), *this,
                 detail::opcode::ping, payload}();
     return init.result.get();
 }
@@ -259,7 +259,7 @@ async_pong(ping_data const& payload, WriteHandler&& handler)
         void(error_code)> init{handler};
     ping_op<BOOST_ASIO_HANDLER_TYPE(
         WriteHandler, void(error_code))>{
-            init.completion_handler, *this,
+            std::move(init.completion_handler), *this,
                 detail::opcode::pong, payload}();
     return init.result.get();
 }
diff --git a/include/boost/beast/websocket/impl/read.ipp b/include/boost/beast/websocket/impl/read.ipp
index 369d3977..8ea8204a 100644
--- a/include/boost/beast/websocket/impl/read.ipp
+++ b/include/boost/beast/websocket/impl/read.ipp
@@ -59,7 +59,7 @@ class stream<NextLayer>::read_some_op
 
 public:
     read_some_op(read_some_op&&) = default;
-    read_some_op(read_some_op const&) = default;
+    read_some_op(read_some_op const&) = delete;
 
     template<class DeducedHandler>
     read_some_op(
@@ -683,7 +683,7 @@ public:
         boost::asio::associated_allocator_t<Handler>;
 
     read_op(read_op&&) = default;
-    read_op(read_op const&) = default;
+    read_op(read_op const&) = delete;
 
     template<class DeducedHandler>
     read_op(
@@ -839,7 +839,7 @@ async_read(DynamicBuffer& buffer, ReadHandler&& handler)
         DynamicBuffer,
         BOOST_ASIO_HANDLER_TYPE(
             ReadHandler, void(error_code, std::size_t))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 buffer,
                 0,
@@ -927,7 +927,7 @@ async_read_some(
         DynamicBuffer,
         BOOST_ASIO_HANDLER_TYPE(
             ReadHandler, void(error_code, std::size_t))>{
-                init.completion_handler,
+                std::move(init.completion_handler),
                 *this,
                 buffer,
                 limit,
@@ -1311,7 +1311,7 @@ async_read_some(
         void(error_code, std::size_t)> init{handler};
     read_some_op<MutableBufferSequence, BOOST_ASIO_HANDLER_TYPE(
         ReadHandler, void(error_code, std::size_t))>{
-            init.completion_handler,*this, buffers}(
+            std::move(init.completion_handler), *this, buffers}(
                 {}, 0, false);
     return init.result.get();
 }
diff --git a/include/boost/beast/websocket/impl/write.ipp b/include/boost/beast/websocket/impl/write.ipp
index c99bdf3b..dfb719dc 100644
--- a/include/boost/beast/websocket/impl/write.ipp
+++ b/include/boost/beast/websocket/impl/write.ipp
@@ -54,7 +54,7 @@ class stream<NextLayer>::write_some_op
 
 public:
     write_some_op(write_some_op&&) = default;
-    write_some_op(write_some_op const&) = default;
+    write_some_op(write_some_op const&) = delete;
 
     template<class DeducedHandler>
     write_some_op(
@@ -728,7 +728,7 @@ async_write_some(bool fin,
         void(error_code, std::size_t)> init{handler};
     write_some_op<ConstBufferSequence, BOOST_ASIO_HANDLER_TYPE(
         WriteHandler, void(error_code, std::size_t))>{
-            init.completion_handler, *this, fin, bs}(
+            std::move(init.completion_handler), *this, fin, bs}(
                 {}, 0, false);
     return init.result.get();
 }
@@ -784,7 +784,7 @@ async_write(
         void(error_code, std::size_t)> init{handler};
     write_some_op<ConstBufferSequence, BOOST_ASIO_HANDLER_TYPE(
         WriteHandler, void(error_code, std::size_t))>{
-            init.completion_handler, *this, true, bs}(
+            std::move(init.completion_handler), *this, true, bs}(
                 {}, 0, false);
     return init.result.get();
 }
diff --git a/test/beast/http/fields.cpp b/test/beast/http/fields.cpp
index 0b982db6..7897ed59 100644
--- a/test/beast/http/fields.cpp
+++ b/test/beast/http/fields.cpp
@@ -24,7 +24,7 @@ namespace http {
 class fields_test : public beast::unit_test::suite
 {
 public:
-    template <class T>
+    template<class T>
     class test_allocator
     {
     public:
@@ -32,7 +32,8 @@ public:
 
         test_allocator() noexcept(false) {}
 
-        template <typename  U, typename = typename std::enable_if<!std::is_same<test_allocator, U>::value>::type>
+        template<class U, class = typename
+            std::enable_if<!std::is_same<test_allocator, U>::value>::type>
         test_allocator(test_allocator<U> const&) noexcept {}
 
         value_type*
@@ -55,7 +56,7 @@ public:
             return true;
         }
 
-        template <class U>
+        template<class U>
         friend
         bool
         operator!=(test_allocator<T> const& x, test_allocator<U> const& y) noexcept
diff --git a/test/extras/include/boost/beast/test/stream.hpp b/test/extras/include/boost/beast/test/stream.hpp
index 3352b988..a75bbde4 100644
--- a/test/extras/include/boost/beast/test/stream.hpp
+++ b/test/extras/include/boost/beast/test/stream.hpp
@@ -488,7 +488,7 @@ async_read_some(
             return boost::asio::post(
                 in_->ioc.get_executor(),
                 bind_handler(
-                    init.completion_handler,
+                    std::move(init.completion_handler),
                     ec,
                     0));
     }
@@ -506,7 +506,7 @@ async_read_some(
             boost::asio::post(
                 in_->ioc.get_executor(),
                 bind_handler(
-                    init.completion_handler,
+                    std::move(init.completion_handler),
                     error_code{},
                     bytes_transferred));
         }
@@ -522,7 +522,7 @@ async_read_some(
             boost::asio::post(
                 in_->ioc.get_executor(),
                 bind_handler(
-                    init.completion_handler,
+                    std::move(init.completion_handler),
                     ec,
                     0));
         }
@@ -531,7 +531,7 @@ async_read_some(
             in_->op.reset(new read_op_impl<BOOST_ASIO_HANDLER_TYPE(
                 ReadHandler, void(error_code, std::size_t)),
                     MutableBufferSequence>{*in_, buffers,
-                        init.completion_handler});
+                        std::move(init.completion_handler)});
         }
     }
     return init.result.get();
@@ -605,7 +605,7 @@ async_write_some(ConstBufferSequence const& buffers,
         return boost::asio::post(
             in_->ioc.get_executor(),
             bind_handler(
-                init.completion_handler,
+                std::move(init.completion_handler),
                 boost::asio::error::connection_reset,
                 0));
     BOOST_ASSERT(out->code == status::ok);
@@ -616,7 +616,7 @@ async_write_some(ConstBufferSequence const& buffers,
             return boost::asio::post(
                 in_->ioc.get_executor(),
                 bind_handler(
-                    init.completion_handler,
+                    std::move(init.completion_handler),
                     ec,
                     0));
     }
@@ -632,7 +632,7 @@ async_write_some(ConstBufferSequence const& buffers,
     boost::asio::post(
         in_->ioc.get_executor(),
         bind_handler(
-            init.completion_handler,
+            std::move(init.completion_handler),
             error_code{},
             bytes_transferred));
     return init.result.get();
@@ -702,18 +702,11 @@ class stream::read_op_impl : public stream::read_op
         lambda(lambda&&) = default;
         lambda(lambda const&) = default;
 
-        lambda(state& s, Buffers const& b, Handler&& h)
+        template<class DeducedHandler>
+        lambda(state& s, Buffers const& b, DeducedHandler&& h)
             : s_(s)
             , b_(b)
-            , h_(std::move(h))
-            , work_(s_.ioc.get_executor())
-        {
-        }
-
-        lambda(state& s, Buffers const& b, Handler const& h)
-            : s_(s)
-            , b_(b)
-            , h_(h)
+            , h_(std::forward<DeducedHandler>(h))
             , work_(s_.ioc.get_executor())
         {
         }
@@ -772,13 +765,9 @@ class stream::read_op_impl : public stream::read_op
     lambda fn_;
 
 public:
-    read_op_impl(state& s, Buffers const& b, Handler&& h)
-        : fn_(s, b, std::move(h))
-    {
-    }
-
-    read_op_impl(state& s, Buffers const& b, Handler const& h)
-        : fn_(s, b, h)
+    template<class DeducedHandler>
+    read_op_impl(state& s, Buffers const& b, DeducedHandler&& h)
+        : fn_(s, b, std::forward<DeducedHandler>(h))
     {
     }