template< class WriteHandler> DEDUCED async_pong( ping_data const& payload, WriteHandler&& handler);
This function is used to asynchronously send a pong frame, which is usually sent automatically in response to a ping frame from the remote peer.
The algorithm, known as a composed asynchronous operation,
is implemented in terms of calls to the next layer's
function. The program must ensure that no other calls to
websocket::stream::async_pong are performed until
this operation completes. If a close frame is sent or received before the
pong frame is sent, the error received by this completion handler will
net::error::operation_aborted. WebSocket allows pong
frames to be sent at any time, without first receiving a ping. An unsolicited
pong sent in this fashion may indicate to the remote peer that the connection
is still active.
The payload of the pong message, which may be empty. The implementation will not access the contents of this object after the initiating function returns.
The completion handler to invoke when the operation completes. The implementation takes ownership of the handler by performing a decay-copy. The equivalent function signature of the handler must be:
void handler( error_code const& ec // Result of operation );
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