template< class WriteHandler> async_return_type< WriteHandler, void(error_code)> async_ping( ping_data const& payload, WriteHandler&& handler);
This function is used to asynchronously send a ping frame to the stream. The function call always returns immediately. The asynchronous operation will continue until one of the following is true:
This operation is implemented in terms of one or more calls to the next
functions, and is known as a composed operation. The
program must ensure that the stream performs no other writes until this
If a close frame is sent or received before the ping frame is sent, the
completion handler will be called with the error set to
The payload of the ping message, which may be empty.
The handler to be called when the read operation completes. Copies will be made of the handler as required. The 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