template< class ConstBufferSequence, class WriteHandler> void-or-deduced async_write_some( ConstBufferSequence const& buffers, WriteHandler&& handler);
This function is used to asynchronously write data from the stream. The function call always returns immediately.
One or more data buffers to be written to the stream. Although the buffers object may be copied as necessary, ownership of the underlying memory blocks is retained by the caller, which must guarantee that they remain valid until the handler is called.
The handler to be called when the operation completes. Copies will be made of the handler as required. The equivalent function signature of the handler must be:
void handler( error_code const& error, // result of operation std::size_t bytes_transferred // number of bytes transferred );
Regardless of whether the asynchronous operation completes immediately
or not, the handler will not be invoked from within this function.
Invocation of the handler will be performed in a manner equivalent