New buffer sequence classes are provided to allow full
control over the serialization of chunk-encoded message
payloads:
* chunk_header
A ConstBufferSequence representing the chunk header.
It includes a hexadecimal-encoded size, an optional
set of chunk extensions, and the trailing CRLF
required to denote the end of the chunk header.
This allows the caller to manually serialize the chunk
body in one or more calls to a stream output function.
The caller must also output an object of type `chunk_crlf`
to the stream to indicate the end of the chunk body.
* chunk_crlf
A small ConstBufferSequence that simply represents
the two character sequence "\r\n" (CRLF). This is needed
for the case where the caller wants to output a chunk
body as a series of buffers (i.e. "chunking a chunk").
* chunk_body
A ConstBufferSequence representing a complete chunk.
This includes the size, an optional set of chunk extensions,
a caller provided buffer containing the body, and the
required CRLF that follows.
* chunk_final
A ConstBufferSequence representing a final chunk. It
includes an optional set of caller-provided field trailers
* chunk_extensions
A container for building a set of chunk extensions to use
during serialization. The use of the container is optional,
callers may provide their own buffer containing a correctly
formatted set of chunk extensions, or they may use their
own convenience container which meets the requirements.
The basic_fields container is modified to allow construction
outside the context of a message. The container can be used
to provide trailers to `chunk_final`.
Actions Required:
* Remove references to ChunkDecorators. Use the new chunk-encoding
buffer sequences to manually produce a chunked payload body in
the case where control over the chunk-extensions and/or trailers
is required.
basic_file_body is specialized for file_win32:
When serializing file bodies to stream sockets on Windows,
the native platform function ::TransmitFile is used, improving
performance.
These types now perform error-based initialization in
a separate init() functions instead of in the constructor.
Actions Required:
* Modify instances of user-defined BodyReader and BodyWriter
types to perfrom two-phase initialization, as per the
updated documented type requirements.
The serializer member is renamed to keep_alive()
Actions Required:
* Use serializer::keep_alive instead of serializer::close and
take the logical NOT of the return value.
