fix#1416
* Calls to buffer_copy are qualified as net::buffer_copy
* Calls to buffer_size are made unqualified, permitting
argument dependent lookup to take effect.
* Optimize hash calculation and equality for field strings
Experiments show the digest and equality functions taking the
most time. Optimizing L1 cache usage did not show significant
improvements.
This algorithm allows a socket-like object to be closed in
a generic context. The customization point enables user-defined
types to define the close algorithm to use with `close_socket`.
fix#1417
* New get_lowest_layer free function works for any object
* New lowest_layer_type trait works for any object
* New examples and documentation on layered streams
API Changes:
* The member function lowest_layer is removed from all
types provided by the library:
Actions Required:
* Call the free function get_lowest_layer instead of
member lowest_layer.
The nested function lowest_layer and nested type lowest_layer_type
are removed from all stream layers.
Actions Required:
* Remove lowest_layer and lowest_layer_type from user-defined streams.
* Use the get_lowest_layer free function and the lowest_layer_type trait
as needed.
This I/O object wraps an ordinary socket and provides a built-in
timeout and optional bandwidth rate-limiting facility.
Added class template basic_stream_socket
* Meets the requirements of AsyncReadStream and AsyncWriteStream
* Partially supports P1322R0:
"Networking TS enhancement to enable custom I/O executors"
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1322r0.html
A strand or other io_context-compatible executor may be
chosen to use for all asynchronous stream operations.
* Supports independent timeouts on logical operations:
connect, read, write, or both read and write.
* Provides an option for a configurable rate limit
limit on the maximum rates of reading or writing.
* The previous experimental implementation,
`timeout_socket` and related types, is removed.
* stream_socket is an alias for basic_stream_socket which
uses `net::ip::tcp` as its protocol.
Vinnie Falco
Peter Dimov
Damian Jarek
Andrey Semashev
Johan Rönnkvist
Glen Fernandes