Remove dynamic_buffer_ref:

* dynamic_buffer_ref is removed, because Asio / Networking
  has introduced the DynamicBuffer_v2 concept which is incompatible
  with Beast's storage types.

The next version of Beast (1.70) will provide changes to
interoperate with Asio / Networking's new concepts.

include/boost/beast/core.hpp

@@ -24,7 +24,6 @@
 #include <boost/beast/core/buffers_suffix.hpp>
 #include <boost/beast/core/buffers_to_string.hpp>
 #include <boost/beast/core/detect_ssl.hpp>
-#include <boost/beast/core/dynamic_buffer_ref.hpp>
 #include <boost/beast/core/error.hpp>
 #include <boost/beast/core/file.hpp>
 #include <boost/beast/core/file_base.hpp>

include/boost/beast/core/dynamic_buffer_ref.hpp

@@ -1,143 +0,0 @@
-//
-// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
-//
-// Distributed under the Boost Software License, Version 1.0. (See accompanying
-// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-//
-// Official repository: https://github.com/boostorg/beast
-//
-
-#ifndef BOOST_BEAST_CORE_DYNAMIC_BUFFER_REF_HPP
-#define BOOST_BEAST_CORE_DYNAMIC_BUFFER_REF_HPP
-
-#include <boost/beast/core/detail/config.hpp>
-#include <boost/asio/buffer.hpp>
-#include <cstdlib>
-#include <type_traits>
-
-namespace boost {
-namespace beast {
-
-/** A lightweight reference to a dynamic buffer.
-
-    Objects of this type meet the requirements of <em>DynamicBuffer</em>.
-    This is the wrapper returned by the function @ref dynamic_buffer_ref.
-
-    @see dynamic_buffer_ref
-*/
-template<class DynamicBuffer>
-class dynamic_buffer_ref_wrapper
-#if ! BOOST_BEAST_DOXYGEN
-{
-    static_assert(net::is_dynamic_buffer<DynamicBuffer>::value,
-        "DynamicBuffer type requirements not met");
-
-    DynamicBuffer& b_;
-
-public:
-    using const_buffers_type = typename
-        DynamicBuffer::const_buffers_type;
-
-    using mutable_buffers_type = typename
-        DynamicBuffer::mutable_buffers_type;
-
-    dynamic_buffer_ref_wrapper(
-        dynamic_buffer_ref_wrapper&&) = default;
-
-    dynamic_buffer_ref_wrapper(
-        dynamic_buffer_ref_wrapper const&) = default;
-
-    explicit
-    dynamic_buffer_ref_wrapper(
-        DynamicBuffer& b) noexcept
-        : b_(b)
-    {
-    }
-
-    std::size_t
-    size() const noexcept
-    {
-        return b_.size();
-    }
-
-    std::size_t
-    max_size() const noexcept
-    {
-        return b_.max_size();
-    }
-
-    std::size_t
-    capacity() const noexcept
-    {
-        return b_.capacity();
-    }
-
-    const_buffers_type
-    data() const noexcept
-    {
-        return b_.data();
-    }
-
-    mutable_buffers_type
-    prepare(std::size_t n)
-    {
-        return b_.prepare(n);
-    }
-
-    void
-    commit(std::size_t n)
-    {
-        b_.commit(n);
-    }
-
-    void
-    consume(std::size_t n)
-    {
-        b_.consume(n);
-    }
-}
-#endif
-;
-
-/** Return a non-owning reference to a dynamic buffer.
-
-    This function returns a wrapper which holds a reference to the
-    passed dynamic buffer. The wrapper meets the requirements of
-    <em>DynamicBuffer</em>, allowing its use in Networking algorithms
-    which want to take ownership of the dynamic buffer. Since Beast
-    dynamic buffers are true storage types, they cannot be used directly
-    with functions that take ownership of the dynamic buffer.
-
-    @par Example
-    This function reads a line of text from a stream into a
-    @ref beast::basic_flat_buffer, using the net function `async_read_until`.
-    @code
-    template <class SyncReadStream>
-    std::size_t read_line (SyncReadStream& stream, flat_buffer& buffer)
-    {
-        return net::read_until(stream, dynamic_buffer_ref(buffer), "\r\n");
-    }
-    @endcode
-
-    @param buffer The dynamic buffer to wrap. Ownership of the buffer is
-    not transferred, the caller is still responsible for managing the
-    lifetime of the original object.
-
-    @return A wrapper meeting the requirements of <em>DynamicBuffer</em>
-    which references the original dynamic buffer.
-
-    @see dynamic_buffer_ref_wrapper
-*/
-template<class DynamicBuffer>
-dynamic_buffer_ref_wrapper<DynamicBuffer>
-dynamic_buffer_ref(DynamicBuffer& buffer) noexcept
-{
-    static_assert(net::is_dynamic_buffer<DynamicBuffer>::value,
-        "DynamicBuffer type requirements not met");
-    return dynamic_buffer_ref_wrapper<DynamicBuffer>(buffer);
-}
-
-} // beast
-} // boost
-
-#endif